Question

Universal donor is
A) O Rh+
B) O Rh-
C) AB Rh+
D) AB Rh-

Answer 1

Hint: Blood groups or blood type is basically classification of blood on the basis of absence and presence of antibodies and inherited antigenic substances. Universal donor is basically a blood type which can be safely given to people of other blood types.

Complete answer:
Rhesus or Rh blood group is named after the rhesus monkeys in which they were first discovered. Individuals either belong to the Rh-positive (Rh+) or Rh-negative (Rh-) Rhesus blood group. People with the Rh+ blood group have D antigens on the surface of their red blood cells, while Rh- individuals do not.
Let’s discuss the question and find the correct answer.

>Option A: Individuals with blood group O, can donate blood to individuals of any ABO blood group (i.e., A, B, O, or AB). Blood group O-positive cannot be given to any Rh-negative individual. Hence, O Rh+ is not a universal donor. Therefore, this is an incorrect option.

>Option B: Individuals with O- blood type is the universal donor because their red blood cells can be transfused into any patient, regardless of blood type. The blood cells of blood group O-negative carry 'no antigen', it can be given to any other group and is thus called a universal donor. Therefore, this is the correct option.

>Option C: An individual donor who has the blood group AB+ with positive Rh is regarded as a universal recipient. They can take blood or RBCs from any kind of blood type. Therefore, this is an incorrect option.

>Option D: An individual donor who has a blood group AB- with negative Rh is regarded as a universal plasma donor. They can give their plasma to the individuals having any other blood type. Therefore, this is an incorrect option.

Thus, the correct answer is option (B) O Rh-

Note: Scientist Karl Landsteiner first described the ABO system of blood group and he was the first who stated that there are four types of the blood group present, i.e. A, B, AB, and O. On the contrary, the universal acceptor is AB.