Each sentence contains an underlined synonym for the word change. In which sentence does the underlined word have the most positive connotation?
A
If you modify the engine yourself, then you will void the warranty.

B
I vary my lunch from day to day so that I do not get bored.

C
After the airline lost my bag, I insisted that they upgrade my seat to first class.

D
Sid found a problem in the organization of his essay, so he plans to revise it.