The Gene "C" Codes for the Membrane-Associated Protein C,responsible for Signal

The gene "C" codes for the membrane-associated protein C,responsible for signal transduction.A mutant allele of this gene,C^m,encodes a malfunctioning C protein,which has the same size as the wild type and associates with the plasma membrane like the wild type,but it has no function in signal.With respect to the expression of the C proteins,the wild-type allele is:

A) codominant to the C^m allele.
B) dominant to the C^m allele.
C) haploinsufficient.
D) incompletely dominant to the C^m allele.
E) recessive to the C^m allele.