Select the correct statement about lymphoid tissue.
a. t lymphocytes act by ingesting foreign substances.
b. lymphoid tissue is predominantly reticular connective tissue.
c. once a lymphocyte enters the lymphoid tissue, it resides there permanently.
d. lymphoid macrophages secrete antibodies into the blood.

Option B.

Explanation:

Lymphoid tissue is a part of immune system which helps to protect body from microbial infection and foreign bodies. Lymphoid tissue contains lymphocytes and is present in the whole body.

Reticular connective tissue is a type of connective tissue formed with a network of several  reticular fibers and forms stroma which is found in the lymphoid tissues.

Lymphoid tissue involves Monocytes or Macrophages, lymphocytes ( B Cells and T Cells) and other free cells located in a reticular meshwork.

Hence, correct option is B. Reticular connective tissue or its meshwork give rise to lymphoid tissues.