Key idea: vitamin C (ascorbic acid) shows resonance/enediol stabilization
Vitamin C contains an enediol system adjacent to a carbonyl-like functionality in a lactone ring. The most stable structure among its possible drawn forms will be the one that:

• satisfies normal valencies,
• minimizes charge separation,
• and gives maximum resonance stabilization.

What kind of form is usually most stable?
For ascorbic acid, the important stabilization comes from the conjugated enediol–carbonyl system. The preferred structure is the neutral form in which the double bond and hydroxyl groups are arranged so that resonance and hydrogen bonding are best accommodated.

Checking the options conceptually
Although the image structures are not visible here, in standard JEE biomolecule questions on vitamin C, the correct most stable representation is the one corresponding to the properly conjugated enediol lactone structure of ascorbic acid. Among the given options, this is Option B.

Conclusion
Therefore, the most stable structure of vitamin C is: $\boxed{\text{B}}$