Definition: 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'.
Input: Question: Point out the correct answer regarding B lymphocytes. 
 Options:  <1> Its two main subpopulations are called B-helper and B-cytotoxic. <2> They are the cells responsible for the production of antibodies in the rejection of an autologous transplant of hematopoietic progenitors. <3> They are the target cells of the anti-CD20 monoclonal antibody (rituximab). <4> They require co-stimulation CD20-CD19 for the expression of the CD3 molecule on its surface. <5> It is the type of majority lymphocyte in the peripheral blood of patients with Bruton's disease.
