The correct answer is: A. Hot : Angry
Dubious means doubtful or uncertain. Certain means sure or confident. Hot means having a high temperature. Angry means feeling or showing annoyance or displeasure.
In the original pair, dubious is the opposite of certain. In the answer pair, hot is the opposite of cold. Therefore, the answer pair has the same relationship as the original pair.
The other options are incorrect because they do not have the same relationship as the original pair. For example, in the option pair long : elongated, long is not the opposite of elongated. Long means having a great distance from end to end. Elongated means made or drawn out longer than usual.