Hint: The question demands the completion of the sentence by filling the most helping verb and verb combination from the options, according to tenses in English grammar. Each option comprises a helping or auxiliary verb and the main verb. These types of sentences that have auxiliary verbs are generally in the perfect or continuous tense.
Since the sentence lacks a verb, the answer must be a verb. The options contain a verb with an auxiliary verb. Therefore, we must consider both the aspects of each option. The term 'yet' implies that the action is currently unfinished; meaning, the verb must be in the present tense.
Now let us look at the given options:
Option A) Hadn’t finish – The word 'hadn’t finish' gives the sentence a past perfect tense. Whereas, the words ‘I’m’ and ‘yet’ suggest that the verb should be in the present or the present perfect tense. Also the word ‘finish’ is used incorrectly, as it should have been ‘finished’. Thus, this option is wrong.
Option B) Haven’t finished – In this option the helping verb ‘haven’t’ is used correctly for the present perfect tense. Also the main verb ‘finished’ is used in its correct form i.e. past participle form. Hence, this is the correct option.
Option C) Didn’t finish – This option is similar to option (A) as it also gives the sentence a past perfect tense, whereas we require a present or a present perfect tense for this given question. Hence, this option is incorrect.
Option D) Aren’t finished – The subject in the question is ‘I’ and the verb ‘are’ is used with pronouns like, we and they. Therefore, this option is incorrect.
Thus, the correct answer is Option (B) i.e, I’m sorry, but I haven’t finished the test yet.
Note: Forms of Verbs each verb can take one of five forms: root, third-person singular, present participle, past, and past participle. For e.g. Finish (root or present), finishes (present or third-person singular), finishing (present participle) and finished (past, past participle). With the help of auxiliary or helping verbs like; have, had, will etc. we can write sentences in the past, present as well as the future tenses.