ABO blood type in man is an example of
1. Pleiotropy
2. Incomplete dominance
3. Co-dominance
4. Multiple allelism
Select the code for the correct answer from the options given below

(A) - 1,2 and 3 only

(B) -1,3 and 4 only

(C) - 3 and 4 only

(D) - 1,2 and 4 only