If the tf-idf metric is used to score relevance for search and retrieval, which term has the highest discriminatory power?

You have the following corpus of texts:

“The cat hit the dog.”

“The dog bit the mail carrier.”

“The mail carrier chased the truck.”

“The truck hit the wall while avoiding the dog that chased the cat.”

“The cat climbed the wall.”

If the tf-idf metric is used to score relevance for search and retrieval, which term has the highest discriminatory power?
A . Dog
B . Chased
C . Bit
D . Truck