5) C
Let the dominant allele be (T )and the recessive allele be (t)
T t
T TT (33%) Tt (66%)
t Tt (66%) tt (dead)
There can only be two genotypes present in live offspring. The fetus with genotype (tt) will die.
Possibility of homozygous dominant (i.e. TT) = 1/3 = 33%