Answer:
D. To make sure Florida Elected Hayes
Step-by-step explanation:
At that time, Rutherford Hayes (from Republican party) was in competition with Samuel Tilden (from Democratic party) for the Presidential seat.
Democratic party use illegal tactics to suppress the formers slaves vote who at that time more likely to support the Republican party. They're threatening the African American who dare to get our from their house to vote.
Daniel chamberlain sent a Telegraph stating that he "need more troops" in south Carolina. The purpose of those troops is to fight off the violent mobs hired by the Democratic party and make sure Florida Elected Hayes.