Correct Option (c) Blood group O
Explanation:
Blood group is tested by two types of sera, i.e. anti-A (antibody-A) and anti-B (antibody-B). Persons with blood group O possess both antibodies in their plasma but have no antigens h their RBCs. So, RBCs of blood group 'O' do not show clumping in any of the two sera. That's why, persons with blood group 'O' are called universal donor and they can donate blood to a person with any type of blood group.