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 B is correct as the subject is plural and skiing is used as a noun here. Don't will be used in the second blank as the reply is negative (use of no).
The other options are wrong as go to is not used. Therefore, ski cannot be used to fill the first blank. Also, the subject is plural and therefore, does cannot be used. NO indicates the use of not.
The correct answer is B) Skiing/don't