Answer:
The correct answer would be "Each parent is either M or MN".
Co-dominance is the condition in which both the alleles express themselves completely when present in the heterozygous condition.
The blood group of the offspring can be of M type in two conditions:
1. When both the parents are of M blood group
2. When both the parents are heterozygous for the blood group that is, they both are MN.
