When asking someone to make a choice between two or more things, you need the interrogative adjective quel, meaning "which" or "what."
When, where, why, how? Use interrogative adverbs to ask these informational questions.
Who, what, which one? Use interrogative pronouns to ask these questions, which are a little more complicated in French than in English.
Knowing how to ask questions is essential for making plans, shopping, traveling, getting to know people, and any other activity that requires obtaining information. There are two different types of questions, and different ways to ask each type.
Obviousness, knowledge, certainty, and hope are considered real - at least to the speaker - and therefore do not call for the subjunctive. Using these verbs and expressions in the negative or interrogative, however, indicates doubt: thus the subjunctive is required.