Which sentence contains a prepositional phrase?
a. running all the way, he got there early.
b. with the proper , they'll complete the project early.
c. they sang it, and sang it again.
d. they tried, although they didn't expect to win.

A prepositional phrase typically begins with a preposition, that is a word that specifies the relationship between two concepts, such as "near" or "away"

Here the preposition is "with" and the phrase is "with the proper help" - answer B (the "with" specifies a relation between "they" and "help"