Some Combinations of Recessive Alleles Cause Problems So Severe That

Some combinations of recessive alleles cause problems so severe that a may fetus cease to develop.Such lethal allele combinations appear to alter Mendelian ratios because

A) carriers do not constitute a progeny class.
B) they do not show a 1:2:1 genotypic ratio.
C) homozygotes for the lethal allele do not appear as a progeny class.
D) homozygotes for the lethal allele pass it on to half their offspring.