It Could Help Meet Transplant Needs to Use a Patient's

It could help meet transplant needs to use a patient's own stem cells to grow a human liver in a pig embryo modified by CRISPR.As an additional and essential step in the process to ensure the liver is safe for the patient,CRISPR should be used to

A) knock out all of the pig brain genes to prevent the pig brain cells from infecting the patient.
B) insert human immune cell DNA into the pig embryo to make it more similar to the patient.
C) insert human hemoglobin DNA into the pig embryo to make it possible for the growing pig to support the human liver.
D) knock out all of the porcine endogenous retrovirus (PERV) genes to prevent infection of the human patient with porcine endogenous retroviruses.