Which of the Following Studies Would Lie Outside of an Ecologists

Which of the following studies would lie outside of an ecologists skill set?

A) Studying the progression of an outbreak of HIV in sub Sahara Africa.
B) Developing a management plan for the preservation of an endangered species.
C) Proposal to develop a solar power field on the edge of a major urban area.
D) Management plan to clean up a section of the Mississippi River that has become polluted due to sewage discharge.
E) All of these are part of an ecologists skill set.