What will come in the blank? Jack ........ no one listened to, was right (a)whom (b)whose?

Now learn the dative case. Suppose I say "Give me your book." The word 'me' is in the dative case because what I mean is "give TO me". The dative case is any time you have to, from, for, by, of, and so on. The dative form of who is whom.

"Jack, to whom no one listened, was right."

The preposition goes before the word it applies to, but that rule is not always followed. Winston Churchill was scolded for ending sentences with prepositions, and he replied "That is the sort of arrogant pedantry up with which I will not put."