In a free-enterprise system, producers decide

a. how much to charge.

b. which services to buy.

c. where to shop for goods.

d. which goods interest them

In a free-enterprise system the producers decide over what products to produce, how to produce then (with what ingredients and what machinery), when and where to produce them and how much to sell them for - the correct answer is a).

The other options are the decisions of the consumers.