An antibody molecule consists of:

Explanation

An antibody molecule, also known as an immunoglobulin, is a Y-shaped protein that plays a critical role in the immune response by recognizing and binding to antigens. Its structure includes two identical light chains and two identical heavy chains, which are connected by disulfide bonds. This configuration allows antibodies to specifically bind to antigens. Option A is incorrect because it only mentions light chains. Option B is incorrect because it only mentions heavy chains. Option D is incorrect because it suggests the heavy chains are non-identical, which is not the case.