I think the analogy is going for opposites (the opposite of sound is silence) and so I would think that the opposite of "effective" would be "ineffective." In regard to an argument or statement, you could also use the word "weak."
Answer:
In protest Guernica was painted by Picasso
Explanation:
something bad is going on at that house
hope this helps
The wrong answer is b, that some other gold diggers had rigged the sled.
