Question

Which of the following have both surfaces(flat and curved) ?

• A. Ball
• B. An apple
• C. Drum
• D. Clock

Answer 1

Answer: (C), (D)

The correct options are
C Drum
D Clock

The boundary surrounding the drum is curved and the and the circular side on which it is beaten is plane.

Similarly the boundary of clock is curved and the glass side is plane.

So options $C$ and $D$ are correct.