Task: Question Answering
Input (English): Question: What group of amino acids, when they are part of the proteins, can be phosphorylated? 
 Options:  <1> Val, Ser, Thr. <2> Phe, Ala, Gly. <3> Val, Glu, Asp. <4> Tyr, Ser, Thr. <5> Lys, Ser, Ile.
Output (English): 4