Which of the following pairs is wrongly matched?

The correct option is B Starch synthesis in pea : Multiple alleles. XO type sex determination pattern is found in certain insects. In this method of sex determination, a female has two X chromosomes (called XX) while the male has only one X chromosome (called XO). For example, Grasshopper. Starch synthesis in pea is controlled by a single gene having alleles B and b. Linkage is a phenomenon of genetic inheritance in which genes of a particular chromosome show their tendency to inherit together. Linkage was discovered by T.H. Morgan in Drosophila melanogaster. Codominance is a phenomenon in which both alleles of a pair express themselves fully in the F1 hybrid. A good example of codominance is human ABO blood grouping in which the four main blood groups A, B, AB and O controlled by three alleles. So, the correct answer is option 2