The correct option is E any / that / you
We use any for indefinite quantities in questions and negative sentences, here, an indefinite time. We use"that" to introduce defining relative clauses, here, the clause that defines the convenience of time. The third blank requires an object pronoun in the second person as the object of the sentence, "you".Hence, Option C is correct. The rest of the options do not adhere to this rule, hence incorrect.