Task: Question Answering
Input (English): Question: Liquid chromatography in normal phase: 
 Options:  <1> It uses a column with apolar groups that interact with the apolar part of the analytes differentially. <2> It is a mode of operation that employs a polar stationary phase with a low polarity mobile phase. <3> It uses highly polar mobile phases such as alkanes or chloroalkanes. <4> It is a mode of operation that employs a non-polar surface with a mixed aqueous / organic mobile phase. <5> It uses stationary phases with a large number of hydrophobic alkyl ligands.
Output (English): 2