Which one of the following antibodies is released through colostrum?

The correct answer is Option (2) → IgA

The newborn gets ready-made antibodies from its mother in the first milk, colostrum. This is passive immunity: the baby does not make these antibodies itself.

Option (1) IgM — Incorrect. IgM is made first when the body meets a new infection, in its own primary response.

Option (2) IgA — Correct. Colostrum has abundant IgA, which protects the infant’s gut and airways.

Option (3) IgE — Incorrect. IgE is the antibody made in allergy, in response to pollen, dust or mites.

Option (4) IgG — Incorrect. IgG is the antibody that passes to the foetus through the placenta before birth, not the antibody of colostrum.

NCERT Extract:
Active and Passive Immunity – “When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity. … The yellowish fluid colostrum secreted by mother during the initial days of lactation has abundant antibodies (IgA) to protect the infant.”