Among four friends A, B, C and D. who is the heaviest ? I. B is heavier than A. but lighter than D. II. C is lighter than B.

• If the data in statement I alone are sufficient to answer the question
• If the data in statement II alone are sufficient answer the question
• If the data either in I or II alone are sufficient to answer the question;
• If the data in both the statements together are needed.