Answer
b. a lymph node
Work Step by Step
Lymph nodes are the only lymphatic organs that have both afferent and efferent lymphatic vessels. Lymph nodes typically have several afferent lymphatic vessels leading into the node and 1-3 efferent lymphatic vessels leading out of the node.
The spleen, the tonsils, Peyer patches, and the thymus do not have both afferent and efferent lymphatic vessels.
