An information processing system consists of seven stations - M,N,P,Q,R,S and T. Every request is classified as either normal or priority. Requests for information are processed in the following ways:
(i) All normal requests are received by either M or N, and all priority requests are received by M or Q.
(ii) All requests processed by M are then sent to T.
(iii) All requests processed by N are then sent to S.
(iv) Normal requests processed by T'are then sent to P, priority requests processed by T are then sent to Q.
(v) All requests processed by S are then sent to cither T or P.
(vi) Normal requests processed by P are then sent to Q, and prioriy requests processed by P are then sent to R.
(vii) All requests processed by Q are then sent to either P or R.
(viii) R is the station which issues a final response.
Any request that is first received by M and is finally received by R must also have previously been processed by
I. T
II. Q
III. P

Options

A. I only
B. III only
C. I and II only
D. I and III only

Answer

C

Explanation

This is a "network" set. Begin by drawing the diagram :
All normal requests are received by either M or N, and all priority requests are received by M or Q :

All requests processed by Q are then sent to either P or R:

A normal request received by M must be processed by T, P and Q before it goes to R. A priority request received by M must go to both T and Q but need not go to P before it is passed to R Q can forward a priority request directly to R.