Assertion: All birds, except the ones like koel (cuckoo) build nests for retiring and taking rest during night time (day time for nocturnal).
Reason: Koel lays its eggs in the nests of tailor bird.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not correct explanation of A
(c) A is true but R is false
(d) A and R are false