Q: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Question: They are primary lymphoid organs:
Options: <1> Spleen and lymph nodes <2> The spleen and bone marrow. <3> The thymus and the bone marrow. <4> The pineal gland <5> Peyer's plates and tonsils.
A:
3