Why did Rod Rosenstein appoint Robert Mueller III as a special counsel in May 2017?
a. to investigate nepotism within the Trump administration
b. to examine allegations of sexual harassment by then-candidate Trump
c. to discern if Hillary Clinton violated protocol by using a private email server as secretary of state
d. to investigate the involvement of Russian operatives in the 2016 election
e. to probe financial decisions made by FBI Director James Comey