Consider the following statements about haemoglobin:1. It carries oxygen in the blood.2. It is an iron-containing compound.3. It provides immunity against certain diseases.4. It imparts red colour to the blood.The correct statements out of these are:

• A. 1, 2 and 3
• B. 1, 3 and 4
• C. 2, 3 and 4
• D. 1, 2 and 4