In this section, each item consists of six sentences of a passage. The first and the sixth sentences are given in the beginning as S1 and S6. The middle four sentences in each have been jumbled up and labelled P, Q, R and S. You are required to find the proper sequence of the four sentences
S1: Crude oil obtained from the field is taken to a refinery for treatment.
S6: Lubricating oils of various grades are obtained last of all
P: The gas that comes off later is condensed into paraffin.
Q : This allows substances with different boiling points to be separated.
R : The first vapours to rise when cooled provide the finest petrol.
S: The commonest form of treatment is heating.
The proper sequence should be:

Options

A. SQRP
B. RSPQ
C. QSRP
D. RPQS