When sugar 'X' is boiled with dilute H₂SO₄ in alcoholic solution, two isomers 'A' and 'B' are formed. 'A' on oxidation with HNO₃ yields saccharic acid where as 'B' is laevorotatory. The compound 'X' is :

Stability of $$\alpha$$-Helix structure of proteins depends upon

Given below are two statements.

Statement I : Maltose has two $$\alpha$$-D-glucose units linked at C₁ and C₄ and is a reducing sugar.

Statement II : Maltose has two monosaccharides : $$\alpha$$-D-glucose and $$\beta$$-D-glucose linked at C₁ and C₆ and it is a non-reducing sugar.

In the light of the above statements, choose the correct answer from the options given below :

L-isomer of a compound 'A' (C₄H₈O₄) gives a positive test with [Ag(NH₃)₂]⁺. Treatment of 'A' with acetic anhydride yields triacetate derivative. Compound 'A' produces an optically active compound (B) and an optically inactive compound (C) on treatment with bromine water and HNO₃ respectively. Compound (A) is :