The correct answer is C. 50 %
A male is a carrier of a recessive somatic mutation it means the mutation can be expressed under homozygous condition, when both the alleles with somatic mutation. Thus, in case of a male carrier of a recessive somatic mutation marries to a normal female will produce 50 % their offspring with recessive somatic mutation so, they will be carrier and 50 % offspring are without this mutation.