Here are the answers to your questions: 1. Five deductions specifically disallowed: Capital expenditure* (e.g., cost of acquiring fixed assets). Domestic or private expenses* (expenses not wholly, exclusively, necessarily, and reasonably incurred for business). Depreciation* (as it is replaced by capital allowances). General reserves* (provisions for contingencies, not specific liabilities). Fines and penalties* (for breaches of law or regulations). 2. Four principles of an ideal tax system: Equity (or Equality)*: Taxes should be levied according to the ability to pay, ensuring fairness. Certainty*: The time, manner, and quantity of payment should be clear and certain to the taxpayer and the tax authority. Convenience*: Taxes should be collected at a time and in a manner most convenient for the taxpayer. Economy*: The cost of collecting taxes should be minimal compared to the revenue generated. 3. Composition and function of Joint Tax Board (JTB): Composition: The JTB is composed of the Chairman of the Federal Inland Revenue Service (FIRS), the Chairmen of the State Boards of Internal Revenue (SBIRs) from each state, a representative from the Federal Capital Territory (FCT), and representatives from the Ministry of Finance and other relevant bodies. Function: Its main functions include ensuring uniformity in the application of personal income tax laws, advising the Federal Government on tax matters, and promoting the efficient operation of the tax system across Nigeria. 4. Conditions for issuing Tax Clearance Certificate (TCC): The applicant must have filed all relevant tax returns for the three immediately preceding years of assessment. All taxes due for those years must have been paid or satisfactory arrangements made for their payment. The applicant must provide evidence of income from all sources for the relevant years. The applicant must not be under any tax investigation or have any outstanding tax liabilities. 5. Composition and function of Local Government Revenue Committee (LGRC): Composition: The LGRC is typically composed of the Chairman of the Local Government Council (as Chairman), the Supervisory Councillor for Finance, the Head of the Finance Department, and other members appointed by the Local Government Council. Function: Its primary functions include assessing and collecting taxes and levies due to the Local Government, ensuring proper accounting for all revenues, and advising the Local Government Council on revenue generation and administration. 6. Why the preceding year basis is necessary in the computation of income tax: The preceding year basis is necessary because it provides a definite and ascertainable profit figure* for a completed accounting period. This allows for the assessment of tax on income that has already been earned and finalized, rather than estimating future income, which would be uncertain and prone to error. It simplifies administration and provides certainty for both taxpayers and tax authorities. 7. Three objectives of taxation: Revenue Generation*: To provide funds for government expenditure on public services and infrastructure. Income Redistribution*: To reduce income inequality by taxing higher earners more and using the revenue to support lower-income groups. Economic Stabilization*: To manage economic cycles by using fiscal policy (e.g., increasing taxes during inflation, decreasing during recession) to control aggregate demand. 8. What is personal income tax and company income tax: Personal Income Tax (PIT)*: This is a tax levied on the income of individuals, sole proprietorships, partnerships, and trusts. It includes income from employment, trade, business, profession, and other sources. Company Income Tax (CIT)*: This is a tax levied on the profits of limited liability companies incorporated in Nigeria or foreign companies operating in Nigeria. It is charged on the assessable profits of the company for each year of assessment.