Antibodies are secreted by:

The correct answer is Option (2) → B-Cells

Option (1) T-Cells — Incorrect. T-cells do not secrete antibodies themselves. They only help the B-cells to make them.

Option (2) B-Cells — Correct. B-lymphocytes (B-cells) are the lymphocytes that make antibodies and release them into the blood. Because the antibodies are found in the blood, this response is called the humoral immune response.

Option (3) α-Cells — Incorrect. α-cells are cells of the islets of Langerhans in the pancreas. They secrete the hormone glucagon, not antibodies.

Option (4) β-Cells — Incorrect. β-cells are also islet cells of the pancreas. They secrete the hormone insulin, not antibodies.

NCERT Extract:
Acquired Immunity – “… The primary and secondary immune responses are carried out with the help of two special types of lymphocytes present in our blood, i.e., B-lymphocytes and T-lymphocytes. The B-lymphocytes produce an army of proteins in response to pathogens into our blood to fight with them. These proteins are called antibodies. The T-cells themselves do not secrete antibodies but help B cells to produce them.”