Key idea: D/L notation for sugars

For monosaccharides, the symbols D and L are assigned by comparing the configuration of the chiral carbon farthest from the carbonyl group with that of glyceraldehyde.

• In an aldohexose like glucose, this is C-5.
• If the $-OH$ on $C-5$ is on the right in Fischer projection, it is D.
• If the $-OH$ on $C-5$ is on the left, it is L.

Recall the Fischer projection of D-glucose

The $-OH$ arrangement from $C-2$ to $C-5$ in D-glucose is:

$\text{Right, Left, Right, Right}$

Obtain L-glucose from D-glucose

L-glucose is the enantiomer of D-glucose, so every chiral center is inverted.

Therefore, for L-glucose, the $-OH$ positions from $C-2$ to $C-5$ become:

$\text{Left, Right, Left, Left}$

How to identify the correct option

So the correct Fischer projection of L-glucose must have:

• aldehyde group ($CHO$) at the top,
• $CH_2OH$ at the bottom,
• and $-OH$ pattern from $C-2$ to $C-5$ as:

$L, R, L, L$

Comparison with the stored answer

The stored correct answer is D. This matches the structure expected for L-glucose.

Hence, the correct option is D.