Under the provisions of the United States Constitution and the laws of the United States, the Federal government cannot detain an American citizen indefinitely without cause and is required
either to bring charges against the individual being held, in which case he is entitled to a lawyer,
or that the government must release him.
The parts after "either" and "or" MUST match to mantain parallelism.
is required either X or Ythe first part is "to bring" so I would normally expect to find a "to + VERB" to the other.
I really don't see B as a good answer as well.
If the question were:
is required TO either X or Y, then B would be correct because now the X and Y part match (bring==release)
B) release him
C) to proceed in releasing him
But given the current construct, C has the correct structure but it's not very idiomatic (proceed in releasing)...
I suggest you to use only reliable sources for SC, or you'll get confused