Silver articles become black after some time when exposed to sunlight. Reason (R): It is because silver reacts with carbonates present in the air.

a) Both statement and reason are true, and the reason is the correct explanation of the statement.
b) Both statement and reason are true, but the reason is not the correct explanation of the statement.
c) The statement is true, but the reason is false.
d) The statement is false, but the reason is true.