Final answer:
Lymphoma involves the accumulation of malignant lymphocytes in the lymphatic system, particularly in the lymph nodes, making answer c) Lymph nodes the correct choice.
Step-by-step explanation:
Lymphoma is a form of cancer that primarily affects the lymphatic system, specifically involving masses of malignant T and/or B lymphocytes. These malignant cells collect in various parts of the body including the lymph nodes, spleen, and to a lesser extent, the liver and other tissues. Thus, the correct answer to the student's question is c) Lymph nodes, as they are a central component in the aggregation of these malignant lymphocytes.