Which of the following is the correct structure of L-Glucose?

Step 1: Fisher Projection of D-Glucose — The $\text{D-isomer}$ of glucose has the hydroxyl ($-\ce{OH}$) groups on the chiral centers C2, C3, C4, C5 as right, left, right, right.

Step 2: L-Configuration — The $\text{L-isomer}$ is the enantiomer, requiring the inversion of all chiral centers.

Step 3: Matching Structure — In $\text{L-glucose}$, the orientation becomes left, right, left, left. This matches structure (a) in the provided image.

Key Point: The D/L prefix refers to the bottom-most chiral carbon (C5 for glucose).