The practice of taking performance-boosting drugs among athletes  but checking it is not going to be easy (P)    is generally conceded to be unfair (Q)    of the detection technology (R)    for the user is generally one jump ahead (S)

The proper sequence should be:

In this question each  items consists of a word in capital letters, followed by four…

In this question each  items consists of a word in capital letters, followed by four…

In this question each  items consists of a word in capital letters, followed by four…

In this question each  items consists of a word in capital letters, followed by four…

In this question each  items consists of a word in capital letters, followed by four…