This question is all about understanding the food chain.
This food chain shows us that shrimp eats phytoplankton, copepods eat shrimps, sunfish eats copepods, and that sharks eat sunfish.
Removing or decreasing one of those variables will put in danger every specie that eats it since its food source will drastically decrease, thus making competition higher.
Following this logic, the correct answer to this question is "The shark population would decrease".
