Explanation

(b)
Ninhydrin test is given by proteins (or amino acids). Benedict test is positive for aldehydes and monosaccharides. (Benedict’s solution is Cu (II) sulphate complexed with citrate anion. Aldehydes and monosaccharides reduced it to red coloured $\left( Cu_{2}O \right).$
The compound is not protein because it gives negative ninhydrin test.
The compound is monosaccharide because it gives positive Benedict test.