Question

Which course is taught by S?

• A. C
• B. E
• C. Either C or D
• D. D

Answer 1

The correct option is C Either C or D

Using the three clues we get the following pairings:
P - B - Not April or May
Q - A - March
R - Not C or D - January
Put them together to get the following table.
$\begin{array}{ccccc}A& B& C& D& E\\ Q& P& & & R\\ March& February& & & January\end{array}$
This leaves S and T to be teaching either C or D and either in April or May.
We do not know who teaches C or D (between S and T).
Hence Option (c) is correct.