Deltax Associate Product Developer interview questions

In round 1 mcq based test out of 200 students they only selected 3 students and in round 2 coding test they rejected all of them no one reached to the interview round.I dont't know on what basis they select the students

first round was aptitude assessment round which consist of mcq questions of core subject such as dbms, oops, computer networks etc. second round consist of coding test which contains five question 2 - easy , 2-medium, 1- hard