In Relation to Cybercrime, What Was the Controversy That Surrounded

In relation to cybercrime, what was the controversy that surrounded the 2016 US Presidential campaign?

A) Chinese hackers attempted to gain access to polling systems within several states
B) Turkish spies in several cities were caught tampering with voters' identification
C) Russian actors used the Internet to interrupt and sow discord during the election
D) Members of the Islamic State attempted to interrupt broadcasts of the presidential inauguration