The problem of 'what to produce' relates to?

The correct answer is Option (1) → The choice of goods and services.

The problem of "what to produce" is one of the central problems of an economy. It refers to the decision regarding which goods and services should be produced and in what quantities, given the limited resources available. This involves choosing between consumer goods, capital goods, necessities, luxuries, etc. So, it directly relates to the choice of goods and services to satisfy the needs and wants of people.