Answer:
correct option C. increase production.
Explanation:
given data
producing  = 37 units Â
marginal cost MC = $3 Â
sell MR = $5 Â
solution
the profit is maximum at MR = MC Â ..............1
and here MR = $5 and MC = $3
then production should be increased up to the  MC = MR = $5
so correct option is C. increase production