I was reading a book when the telephone bell . . . . . . . . A. should ring B. rang C. had rung D. ringing

should ring
rang
had rung
ringing

The correct answer is B. rang.

The sentence is in the past tense, so the verb “ring” should also be in the past tense. The other options are not in the past tense.

A. should ring is in the infinitive form, which is used to express a suggestion, a request, or a possibility.
C. had rung is in the past perfect tense, which is used to express an action that happened before another action in the past.
D. ringing is the present participle form, which is used to express an action that is happening now.