Answer:
I believe its answer A
Step-by-step explanation:
because so many mouse genes are similar to human genes, geneticists can generate knockout mice in which the mouse counterpart of a human gene of interest is deleted or disrupted. geneticists use the term to refer to a mouse that has been genetically engineered such that at least one of its genes is functionally inactivated (i.e. the inactivated gene is "knocked out")