A C you actually earned is worth more than an A you’d have to keep lying about.

An honest result you can stand behind costs less over time than a better one you have to maintain. Anything built on a false account needs ongoing management, and that management grows as more gets stacked on top of it. The grade you earned is finished the moment it is given. The other kind never quite finishes.

If you are near a line you would rather not cross, ask what the upkeep would be. Take the lower result with the clear conscience, then fix what caused it with real work. Honest ground is worth less on paper and far more to stand on.