Question

Which verb mood would work best for expressing a wish that is unlikely to come true?

Indicative
Imperative
Conditional
Subjunctive

Answer 1

The subjunctive mood is the best.

The subjunctive is rarely used in colloquial English. Totally irrelevant information, but... it is a relic from Latin, where there are many uses for a subjunctive. There is even a special conditional using the subjunctive mood that expresses the exact circumstances you described, which is usually called future less vivid.

Answer 2

The correct answer is D. Subjunctive

Explanation:

In English and other languages, there are different verb moods, these moods indicate if the information is a fact, a command, a request, etc. In the case of subjunctive mood refers to a set of grammatical forms that allow people to express some situation is not real this includes wishes, possibilities, opinions, emotions and other situations that are not likely to happen or have not happen yet, this is the case of some modal verbs such as will, can, could or might used to express possibilities, wishes  that are not considered as real and that are unlikely to come true. Although, the subjunctive mood includes many other grammatical forms. Thus, the mood that is used to express a wish or similar situations that are unlikely to come true is the subjunctive mood.