Complement attaches to immunoglobulin at:
High-Yield Explanation
Ans. is 'd' i.e., Fc fragment (Ref: Ananthanarayan, 8th/e, p. 97)* Fc fragment consist of parts of both H chains, composed of carboxyterminal portion of the H chains and it determines biological properties of Ig molecule such as complement fixation, placental transfer, skin fixation and catabolic rate.