Science tip:
Here’s a very interesting question. Some people answered (1), some people answered (2). Some teachers can’t explain why.
The answer is (2).
The reason is because we don’t know why the bulb doesn’t light up. It could be due to A. It could be due to B. It could be due to a faulty battery or a faulty light.
Answer (1) – if the bulb lights up, you know that B is the culprit. But if the bulb doesn’t light up, you cannot conclude anything anything about A, as it could have been the battery or the lamp.
Answer (2) – if the bulb lights up, you know that A is the culprit. If the bulb doesn’t light up, you know its A is not the culprit.
Thus, the answer is (2).