Natural gas in its native state is colorless and odorless. Mercaptan is the additive that is added to natural gas to make it easier to detect in case of a leak.
Boost the tourist trade always favors aviation. You have to get to a foreign country somehow. D is not the answer.
Creating wealth is not a hindrance to any industry. So A is incorrect.
B is kind of tough to get rid of. If aviation is already there you don't want to compete with an established industry. It is wrong only because C is a better choice.
Answer. C.
The term for community college is education institution. there are different meanings for it, but that is the main one.