Which of the following option(s) is/are correct for starch synthesis in pea seeds controlled by single gene which has two allelic forms B and b?

Solution:

This can be explained as occasionally a single gene product may produce more than one effect. Like in starch synthesis in pea seeds controlled by one gene having two alleles (B and b).
Thus, the phenotype and genotype expressed are
BB-round seed, large starch synthesis
bb-wrinkled seed, less starch synthesis
Bb-round seed, intermediate starch synthesis. 
Thus, if we take size as a phenotype, allele B shows complete dominance over 'b', but if we take starch synthesis as a phenotype, allele B and b shows incomplete dominance.