As the situation has changed,
P : since we last discussed this matter
Q : it was best to contact you
R : it appeared to me
S : without losing time

The proper sequence should be:

A. PQRS

B. PRQS

C. PRSQ

D. SPRQ

Answer: Option B

Solution(By Examveda Team)

As the situation has changed, since we last discussed this matter it appeared to me it was best to contact you without losing time.