Fill in the blank with the most appropriate word.
I _____ a bicycle when I was young.
A verb is used to express an occurrence, action, or state. It is the grammatical centre of the predicate in a sentence.
An auxiliary verb is a verb which gives is used in the formation of tenses, moods, tones, etc.
Option C is correct as the 'when I was young' indicates that we are talking about the past. Here, have' s third form is used (had) as ordinary verb because the main verb is missing.
The other options are wrong as no other tense other than simple past can be used.
The correct answer is C)had