Task: Question Answering
Input (English): Question: When centrifuging human peripheral blood in a density gradient in Ficoll: 
 Options:  <1> The mononuclear cells float on the Ficoll. <2> The lymphocytes remain in the background. <3> The erythrocytes float on the Ficoll. <4> The granulocytes float on the Ficoll. <5> The monocytes remain in the background.
Output (English): 1