Aman is blind-folded and he is asked to differentiate some pairs of items. Which of the following pairs of items can he differentiate? [a] A glass of orange juice and a glass of plain water. [b] A piece of red and a piece of blue cloth. [c] A round ball and a rectangular box. [d] An empty piggy bank and a piggy bank with some coins in it.

• A.  [a] and [d] only                
• B.  [b] and [c] only
• C.  [a], [c] and [d] only          
• D.  [a], [b], [c] and [d]