If Charity wants to be happy on Mondays,
If Mark's thing falls into water,
and if Velma eats fruits with her fingers,
What would Phoebe's favorite insect be ?
All non-function words in each of the first three lines relate to a common concept. The three concepts belong to a pattern, which will help you deduce the concept linked to the fourth line... and hopefully the favorite insect.
Isn't Velma in some famous group ? Isn't Mark ?..