The prepositional phrase " on the park bench " acts as an adjective phrase....it is describing the man...it is answering the question " which man "...the one on the park bench.
It will follow a general noun and is not set off by commas is true regarding a restrictive adjectival clause. Since this clause is restrictive, it means it is essential for the meaning of the noun and cannot be excluded.
The answer is B because if he says he NEEDS to gom then that means he wants to go with what he wants to go with and this will be his final decision.
C, who will you invite to the carnival and fireworks display?