Answer:
b. “I believe A because of B
Explanation:
Claim is trying to assert a point, usually without an evidence or a proof to back it.
Reason is a statement that basically provides valid proof that backs up a point or a statement.
In above question, option b seems to be is correct where a claim is being made and is also backed by reasoning.
The claim would be "I believe A" whereas the reason would be " because of B".
