In the past few months, there has been extensive dispute over if fare hikes should be a first or last recourse in improving the transit system.

The phrase "over if fare hikes should be a first or last recourse" is incorrect because "if" is not the right conjunction for expressing alternatives in formal writing. Instead, we typically use "whether" in such contexts. This helps us eliminate Options A, B and C and zero in on Option D as the correct choice. In B, the phrase "about if" is ungrammatical. Similarly, in C, the phrase "hiking fares as being" is awkward and unidiomatic.