The Correct Answer is Option B: Digestion with papain will give Fab fragment.

Explanation:

1. Introduction:
Antibodies, also known as immunoglobulins (Igs), play a crucial role in the immune system. They are Y-shaped molecules that are produced by plasma cells, a type of white blood cell, in response to the presence of foreign substances (antigens) in the body. Antibodies bind to antigens and help in their neutralization or removal.

2. Structure of an Antibody (IgG):
An antibody molecule, such as Immunoglobulin G (IgG), consists of two identical heavy chains and two identical light chains, held together by disulfide bonds. The antibody molecule has two regions: the Fab region (Fragment antigen-binding) and the Fc region (Fragment crystallizable).

3. Proteolytic Digestion of Antibodies:
Proteases are enzymes that break down proteins by cleaving peptide bonds. Digestion of an antibody molecule using specific proteases leads to the production of various antibody fragments with distinct functions.

4. Digestion with Papain:
Papain is a protease enzyme derived from papaya latex. It cleaves the antibody molecule below the hinge region, resulting in the generation of two Fab fragments and one Fc fragment.

5. Fab Fragment:
The Fab fragment (Fragment antigen-binding) is a monovalent fragment of an antibody that contains the antigen-binding site. It consists of one light chain and the variable (V) and constant (C) regions of one heavy chain. The Fab fragment retains the ability to bind to the antigen.

6. Fc Fragment:
The Fc fragment (Fragment crystallizable) is a divalent fragment of an antibody that does not contain the antigen-binding site. It consists of the constant (C) regions of the two heavy chains. The Fc fragment is responsible for effector functions, such as binding to Fc receptors on immune cells and activating complement.

7. Correct Answer:
Digestion of an antibody molecule, such as IgG, with papain will result in the production of Fab fragments. The Fab fragments retain the antigen-binding site and can bind to antigens, while the Fc fragment is not generated in this process.

8. Incorrect Options:
a) Digestion with papain will not give F(ab)2 fragment. F(ab)2 fragments are generated when an antibody molecule is digested with pepsin, not papain.
c) Digestion with pepsin will not give Fab fragment. Pepsin digestion results in the production of F(ab)2 fragments, not Fab fragments.
d) Digestion with pepsin will not give Fc fragment. Pepsin digestion results in the production of F(ab)2 fragments, not Fc fragments.

Conclusion:
The correct statement regarding the digestion of an IgG molecule using proteases is that digestion with papain will give Fab fragments. This process involves the cleavage of the antibody molecule below the hinge region, resulting in the production of two Fab fragments and one Fc fragment.