Test analysis: Sheep A and C are surrogate ewes, which can provide Dolly with rich nutrition. A is incorrect;
B, Dolly the cloned sheep is not fertilized, so it belongs to asexual reproduction, not the product of transgenic, and B is incorrect;
C, through analysis, it can be concluded that the genetic information is in the nucleus, and C is correct.
D, ABC is strong, and D is incorrect;
So choose: C.