Task: Question Answering
Input (English): Question: Heparin is: 
 Options:  <1> A plasma protein with no net charge with coagulant function. <2> A glycosaminoglycan with high density of sulphate groups in its structure and anticoagulant function. <3> A protease that facilitates the transformation of prothrombin into thrombin. <4> An extracellular matrix protein with no net charge, which gives rise to highly viscous solutions with a lubricating function. <5> A homopolysaccharide with anticoagulant function thanks to the high density of positive charges in its structure.
Output (English): 2