What question does the adverb clause answer?

After I went to bed last night, the telephone rang twice.

when

where

how

why

under (on) what condition

compare/contrast

When

Explanation:

Clause is a group of words that usually consists of subject and predicate. There are two types of it: independent (it can stand alone as a sentence) and dependent (it can not stand alone). Types of dependent clause: adverb, adjective, noun dependent clause. Adverb clause modifies the meaning of a verb, adjective, another clause etc. It usually starts with although, if, after ...

In the given sentence adverb clause is After I went to bed last night and it answers the question when did the telephone ring.