Fill in the blank with the most appropriate word.
I _____ a very good program on TV last night.
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 D is correct as last night indicates the use of simple past tense. Also, simple past tense uses the second form of verb.
The other options are wrong as no other tense other than the simple past tense can be used.
The correct answer is D)saw