When the Human Gene Coding for Insulin Is Introduced into a Mouse

When the human gene coding for insulin is introduced into a mouse embryo, the gene is correctly expressed in the appropriate tissue. This shows that:

A) tissue-specific gene expression is highly conserved during evolution.
B) the introduced gene was edited by the mouse embryo for proper function.
C) the introduced gene was exactly the same as the mouse gene for insulin.
D) mice and humans are not closely related.
E) mouse genes are not tissue specific.