In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.

Let me give you an example: Question: A distension is defined as:
Options: <0> Soft tissue injury. <1> Forced movement of abrupt production. <2> Injury by stretching a muscle. <3> Injury of the joint capsule. <4> Interruption in the continuity of a bone.
The answer to this example can be: nursery
Here is why: Distension means Bloating and swelling in the belly area. It does not have much to do with chemistry, psychology, pharmacology, biology and medicine. Hence, the correct topic is nursery.

OK. solve this:
Question: The simultaneous expression of IgM and IgD as membrane immunoglobulins occurs in:
Options: <0> B cells that respond to thymoindependent antigens. <1> B cells that respond to thymus-dependent antigens. <2> Activated B cells stimulated by Interleukin 4 (IL-4). <3> Immature virgin B cells. <4> Mature virgin B cells.
Answer:
pharmacology