Using Molecular Techniques,researchers Have Knocked Out Both Copies of Gene

Using molecular techniques,researchers have knocked out both copies of gene "G" in a series of genetically identical mouse embryos.These mice develop normally,except for their forelimbs,which are missing several small bones.What can be concluded from the results of this experiment?

A) Gene "G" encodes a protein that is a crucial component of the forelimbs' small bones in mice.
B) Gene "G" encodes a protein that is normally only present in the forelimb cells of developing mice.
C) Gene "G" is necessary for proper development of the forelimbs' small bones in mice.
D) Gene "G" is normally only present in the forelimb cells of developing mice.
E) Gene "G" is normally only transcribed in the forelimb cells of developing mice.