The correct option is C None of the above
Total possible gametes formed by a genotype is = 2n, where n is a number of genes for which it is heterozygous. The given genotype VVRRtt is homozygous for all three genes; thus it will form only one type of all gametes carrying “VRt”. As we know that dihybrid plant is heterozygous for two genes, thus total possible gametes by it = 22 = 4. Similarly, trihybrid and tetrahybrid plants are heterozygous for three and four genes respectively, thus total possible gametes = 23 and 24 = 8 and 16 respectively. A plant heterozygous for one gene makes two types of gametes; 21 = 2. The correct option is D.