The word <em>mood</em> in gramar is used to refer to a verb category depeding on what the cerb expresses. In this case, since the verb expresses a condition, we are dealing with <u>a subjunctive mood</u> sentence.
The<u>subjunctive mood</u> is used to talk about hypothetical, non factual or doubtful conditions using<em> if</em> with the conditional or the past conditional.
When you are speaking to someone you speak to them with respect so d doesn’t work it has to be c because you aren’t only talking about your opinion but you are also talking about other peoples opinions and what they think so the answer is c
