Question

two friends decide to start selling their drone camera aerial footage. which economic question have they answered?
for whom to produce?
how much to produce?
how to produce?
what to produce?

Explanation:

The three basic economic questions are "What to produce?", "How to produce?", and "For whom to produce?". By choosing to sell drone camera aerial footage, the friends have decided what specific good they will offer in the market, which answers the "What to produce?" question. The other options are not addressed here: they haven't decided how much footage to sell, how they will create/process it, or who their target customers are.

Answer:

What to produce?