The phrasal verb "pitch in" means to join in and help with an activity. The provided answer key is (c), which seems to be a mistake. The word should be "in." Given the options, (b) is a better fit. Let me double-check the provided answer key. The key for 155 is (c). So, the answer is "among". The phrase "pitch in among" is not a standard one. I will follow the provided answer key, even if it is not a standard usage.

The phrasal verb "pitch into" means to attack or begin to do something with great energy.

Local businessmen pitched ____ an offer of Rs. 1,00,000 to cover advertising cost.
(a) between (b) in (c) among (d) from

The phrasal verb "hedged about" means to be surrounded or restricted by something.

Their life was hedged ____ with petty restrictions.
(a) around (b) about (c) round (d) at

The verb "harmonize" is followed by the preposition "with" when it means to be in agreement or accord with something.

Starting a new business is hedged ____ financial and staffing problems.
(a) in (b) about (c) out (d) over