Explanation:

In this sentence, the verb "wait" is in the present continuous tense, indicating an action that is happening at the moment of speaking. The subject of the sentence is "we," which is a plural pronoun. Therefore, the correct form of the verb "wait" for this subject in the present continuous tense is "are waiting."

Subject-Verb Agreement:

The subject and verb in a sentence must agree in person and number. In this sentence, the subject "we" is a plural pronoun, so the verb "wait" must also be in the plural form. The present continuous tense for the plural form of the verb "wait" is "are waiting."

Present Continuous Tense:

The present continuous tense is used to describe actions that are happening at the moment of speaking. It is formed with the present tense of the verb "to be" (am, is, are) and the present participle (-ing form) of the main verb. In this sentence, the present continuous tense is used to describe the action of waiting that is happening at the moment of speaking.

Conclusion:

Therefore, the correct answer to the sentence "Hurry up! We ____________ for you. (wait)" is "are waiting." This is because the subject "we" is plural, and the present continuous tense is used to describe an action that is happening at the moment of speaking.