Task: Text Categorization
Input (English): Question: Tα CD4 + lymphocytes: 
 Options:  <0> They are functionally cooperative with B lymphocytes and other T lymphocytes. <1> They recognize native antigens in soluble form. <2> They recognize peptides in the MHC class I context. <3> They are less abundant than CD8 + in human blood. <4> They release perforins.
Output (English): biology