The right answer is Compared to most years, we had little snow this year (c)
English constructions are usually around a certain expression, phrase or word. In this case the focus is on what is happening "this year".
When made to compare, the comparison should also lean on the expression/phrase/word under review.
The comparisons here will be year vs year. Hence the selection of C as our answer.
Understand "Snow" is a constant and thus we shouldn't have a form of comparison to snowstorm, snowfall or forecast.