Ordering of Sentences - Verbal and Reasoning

Directions to SolveIn questions below, each passage consist of six sentences. The first and sixth sentence are given in the begining. The middle four sentences in each have been removed and jumbled up. These are labelled as P, Q, R and S. Find out the proper order for the four sentences.
Q1:

S1: Calcutta unlike other cities kepts its trams.
P : As a result there horrendous congestion.
Q : It was going to be the first in South Asia.
R : They run down the centre of the road
S : To ease in the city decided to build an underground railway line.
S6: The foundation stone was laid in 1972.
The Proper sequence should be:

A PRSQ

B PSQR

C SQRP

D RPSQ

ANS:D - RPSQ

No answer description is available.