A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in the ratio of
(a) 3 : 1 :: Tall : Dwarf
(b) 3 : 1 :: Dwarf : Tall
(c) 1 : 2 : 1 :: Tall homozygous : Tall heterozygous : Dwarf
(d) 1 : 2 : 1 :: Tall heterozygous : Tall homozygous : Dwarf.