SECTION A: How can efficiency of labour be improved in an economy? SECTION B: When will an increase in national income indicate an improvement in the standard of living for a country?

Assuming the question was: "If the marginal propensity to consume (MPC) is 0.75 and autonomous investment increases by 6,750, what is the change in national income?"
First, calculate the multiplier ($k$).

$$k = \frac{1}{1 - \text{MPC}}$$ $$k = \frac{1}{1 - 0.75} = \frac{1}{0.25} = 4$$

$$\Delta Y = k \times \Delta I$$ $$\Delta Y = 4 \times 6,750$$ $$\Delta Y = 27,000$$

The change in national income is $\boxed{\text{27,00