A,a 2-(2a-1)=a 2-2a+1,故此选项错误;
B,a 2+(-2a-3)=a 2-2a-3,故此选项错误;
C,3a-[5b-(2c-1)]=3a-5b+2c-1,故此选项正确;
D,-(a+b)+(c-d)=-a-b+c-d,故此选项错误;
故选:C.
A,a 2-(2a-1)=a 2-2a+1,故此选项错误;
B,a 2+(-2a-3)=a 2-2a-3,故此选项错误;
C,3a-[5b-(2c-1)]=3a-5b+2c-1,故此选项正确;
D,-(a+b)+(c-d)=-a-b+c-d,故此选项错误;
故选:C.