Final answer:
White blood cells, specifically lymphocytes, originate from stem cells in the bone marrow. B cells fully mature in the bone marrow, while T cells migrate to the thymus for maturation.
Step-by-step explanation:
White blood cells, or lymphocytes, develop from stem cells located in the bone marrow. These stem cells differentiate into two main types of lymphocytes: B cells and T cells. B cells mature in the bone marrow, giving the 'B' in their name its significance.
On the other hand, T cells migrate to and mature in the thymus, which is reflected in the 'T' for their designation. Therefore, the white blood cells originate from stem cells in the bone marrow before possibly migrating to other lymphatic tissues for further maturation. Answer to the student's question: White blood cells develop from stem cells located in the bone marrow (Option B).