Final answer:
The correct answer is option C. The sentence is an example of a dangling modifier, which needs to be corrected by placing the modifier closer to the noun it modifies.
Step-by-step explanation:
The sentence in question is an example of a dangling modifier. A dangling modifier is a word or phrase that does not clearly relate to the noun or pronoun it is intended to modify. In this case, the phrase 'Sauced with lumpy gravy' is the dangling modifier because it does not clearly modify the noun 'Gilbert'. To correct the sentence, the modifier needs to be placed closer to the noun it modifies, for example: 'The waitress served Gilbert a plate of gray meatloaf sauced with lumpy gravy.'