Identify the correct option for each of the following questions related to agriculture and its related industries. Choose from the options provided in each question.

The use of crude implements, or basic tools, is a problem that primarily affects agriculture, leading to low productivity.
The correct option is (b).

A tractor is a piece of machinery directly used in agricultural activities, making it a component of agriculture.
The correct option is (d).

Subsistence agriculture is a form of farming where the produce is primarily for the farmer's own consumption, often associated with peasant farming.
The correct option is (c).

Rubber and cotton are grown for sale rather than for direct consumption, making them cash crops.
The correct option is (b).

Poverty is a significant problem that affects and is often intertwined with agriculture, especially in developing economies. Therefore, the statement is true.
The correct option is (b).

Columbite is an ore containing niobium and tantalum, which are used in high-temperature alloys and specialty steels for heat resistance. Tin is also a mineral found in basement complex rocks.
The correct option is (c).

The process of digging deep holes to extract mineral resources from the earth's crust is known as mining.
The correct option is (c).

"Black gold" is a common term used to refer to petroleum (crude oil).