D-Glucose, D-Mannose and D-Fructose form same osazone on reaction with phenyl hydrazine because they have same confuguration at carbon x, y & z. Values of x,y and z are

D -Glucose and D -fructose both form the same osazone, Which statements are correct about the above reaciton?

D -Glucose and D -fructose both form the same osazone, Which statements are correct about the above reaciton?

A : Glucose, Mannose and Fructose form identical osazone. R : Glucose, Mannose and Fructose have identical configuration at 3rd, 4th and 5th carbon atom

(A) D-Glucose and D-Mannose form identical osazone on reaction with excess of phenyl hydrazine (R) D-Glucose and D-Mannose are epimers differing in configuration at C-2 only.

(A) Glucose and fructose give the same osazone. (R) Glucose and fructose have same configu- ration at C_y, C_4 and C_5

In alkalin solution D-glucose, D-mannose and D-fructose are in equilibrium. This reaction is known as

D-glucose and D-fructose have different structures. Why do they form the same product on reacting with excess of phenyl hydrazine ?