In this task, you are given a premise sentence, two possible options and a question word. If the question was cause you should select the option that is a possible cause of the premise sentence, and if the question word was effect you should find the option which is a possible effect of the premise sentence. Answer with "A" or "B".

Let me give you an example: The animal species became endangered. (A) Their habitat was destroyed. (B) Their predators went extinct., Question: cause
The answer to this example can be: A
Here is why: The question word is cause, so we should find the possible cause of the premise. Option A can be the cause of the premise, and the output should be "A".

OK. solve this:
The children knocked over a lamp. (A) They had a pillow fight. (B) They jumped on the bed., Question: cause
Answer:
A