This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Which of the following class specific antigenic determinants of an immunoglobulin is associated with? 
Select and explain. 
A. L - chain, B. H - chain, C. J - chain, D. Variable region
B: H - chain
Answer: B: H - chain 
Explanation: Ans. is 'b' i.e., H - chain(Ref: Chatterjee Shinde, 4th/e, p. 92, 93; Chandrasoma Taylor, 3rd/e, p. 61, 62. Ananthanarayan, 9th/e, p. 94 Table 11.1)* The five classes of Igs are classified based on the amino acids sequence of the heavy chain. The basic immunoglobulin molecule is composed of two heavy (H) chains and two light (L) chains which are connected by disulfide bonds.