Question

Tom and Frank had drank or drunk the new soft drink before.. which answer is it drank or drunk

Answer 1

The correct answer is drunk,which is the past participle of "to drink"
"drank is the S.Past Ex.- I drank 2 beers yesterday
 "drunk" is the past participle used in the Present/past Perfect tenses.

Answer 2

The answer is drunk because drank is in the present.

Had = Past

Tom and Frank Had  

Had means done before

Answer Drunk

Hope it helps