Respuesta :

C. Technically speaking, the VP does preside over the Senate. Usually, this role is extremely limited and the VP rarely attends sessions in the Senate. Technically, the president pro tempore is supposed to preside, but even this is uncommon. The leadership can be quite tricky to figure out.

The VP does have a tie-breaking power on votes. VP Mike Pence used that power on a few controversial confirmations in the Trump Administration. 
The answer to your question is letter C.