In a pond, the primary producer's Spirogyra, an algae; the primary consumer is Daphnia a crustacean; the secondary consumer is the bluegill fish; and the tertiary consumer is smallmouth bass.   What could be expected if the Daphnia were killed by pesticides?

A. The Spirogyra population will die.

B. The bluegills will increase.

C. The Daphnia will eat something else.

D. The smallmouth bass will die.