The average age of P, Q, R and S is 30 years. How old is R? I. The sum of ages of P and R is 60 years. II. S is 10 years younger than R.

• A. I alone sufficient while II alone not sufficient to answer
• B. II alone sufficient while I alone not sufficient to answer
• C. Either I or II alone sufficient to answer
• D. Both I and II are not sufficient to answer
• E. Both I and II are necessary to answer