Task: Question Answering
Input (English): Question: Th1 lymphocytes: 
 Options:  <1> Activate B lymphocytes and eosinophils. <2> Activate macrophages and NK lymphocytes. <3> They secrete mainly IL-4. <4> They promote the production of IgE. <5> They are a type of Treg lymphocytes.
Output (English): 2