Treatment of D-glucose with aqueous NaOH results in a mixture of monosaccharides, which are

The correct option is shown in the image below:

Lobry de Bruyn-Alberda van Ekenstein Transformation:

When D-glucose is treated with a dilute aqueous base such as NaOH, it undergoes a rearrangement known as the Lobry de Bruyn-Alberda van Ekenstein transformation. This reaction involves an enolization process via an endiol intermediate (1,2-enediol).

During this transformation, D-glucose undergoes epimerization at carbon-2 (C-2) as well as aldose-ketose isomerization to form an equilibrium mixture containing three monosaccharides:

1. D-fructose (a ketohexose):
Structure has a carbonyl at C-2 (C=O), with C-3 having -OH on the left, and C-4, C-5 having -OH on the right (along with terminal -CH₂OH groups at C-1 and C-6).

2. D-glucose (the starting aldohexose):
Fischer projection configuration at carbons C-2, C-3, C-4, C-5 is: C-2 (R, -OH on right), C-3 (S, -OH on left), C-4 (R, -OH on right), C-5 (R, -OH on right).

3. D-mannose (the C-2 epimer of D-glucose):
Fischer projection configuration at carbons C-2, C-3, C-4, C-5 is: C-2 (S, -OH on left), C-3 (S, -OH on left), C-4 (R, -OH on right), C-5 (R, -OH on right).

Analyzing the options from the provided images:

- Structure 1 (D-fructose): Shows CH₂OH at top, C=O at C-2, C-3 with -OH on left, C-4 with -OH on right, C-5 with -OH on right, and CH₂OH at bottom.
- Structure 2 (D-glucose): Shows CHO at top, C-2 with -OH on right, C-3 with -OH on left, C-4 with -OH on right, C-5 with -OH on right, and CH₂OH at bottom.
- Structure 3 (D-mannose): Shows CHO at top, C-2 with -OH on left, C-3 with -OH on left, C-4 with -OH on right, C-5 with -OH on right, and CH₂OH at bottom.

Thus, the reaction results in a mixture of D-fructose, D-glucose, and D-mannose, which perfectly corresponds to option (C).