A parent is homozygous and a parent heterozygous for an autosomal recessive gene. What will be the outcome –
(A) 75% children affected (B) No child affected, but all are carriers (C) 50% children affected, rest are carriers (D) 25% children affected, rest are carriers
(C) Autosomal recessive disorders 

Autosomal recessive disorders are manifested in homozygous state, i.e. when both alleles at a given gene locus are mutant.
There may be following five situations -