Final answer:
The correct revision of the sentence is 'The governor signs or vetoes bills.' It concisely captures the governor's legislative powers, including the right to veto which reflects the governor's role in lawmaking.
Step-by-step explanation:
The correct revision of the sentence "It is the governor who signs or vetoes bills." is Option C: "The governor signs or vetoes bills." This option is clear and concise, correctly indicating the role of the governor in the legislative process without redundancy. Governors indeed have significant powers, including the ability to veto legislation, which can either reject a bill in its entirety or, in the case of a line-item veto, reject specific parts of a bill while allowing the rest to become law. While these veto powers serve as an essential check on the legislature, they can sometimes lead to controversy, such as the "Frankenstein" veto, where entire sections of a bill can be restructured, changing its original intent.