Answer:
A. For whom to produce?
Step-by-step explanation:
What to produce does not generate any mathematical sense. Therefore, Option "D" is wrong.
"How to produce" is to know how goods should be produced. Since it does not carry any mathematical equation or function, the option "C" is wrong.
How much to produce is related to for whom to produce. Therefore, we cannot determine how much to produce without finding for whom to produce. So, option B is incorrect.
Option A is correct because we need to determine for whom to produce. It is the primary math for that student.