Step 1: Understanding Kolbe's reaction.
Kolbe’s reaction is a decarboxylation reaction of carboxylates in the presence of a strong base, followed by the addition of carbon dioxide. The reaction given in the question represents the Kolbe reaction, which leads to the formation of a carboxylic acid.
Step 2: Analyzing the options.
(A) Kolbe's reaction: Correct — This is the correct reaction, where sodium phenoxide reacts with carbon dioxide to form salicylic acid.
(B) Sandmeyer's reaction: Incorrect. This involves the conversion of diazonium salts to aryl halides, not a decarboxylation.
(C) Reimer-Tiemann reaction: Incorrect. This reaction involves the introduction of a formyl group to a phenol molecule.
(D) Stephen reaction: Incorrect. This reaction is related to the formation of imines, not a decarboxylation.
Step 3: Conclusion.
The correct answer is (A) Kolbe's reaction, which is a decarboxylation reaction that leads to the formation of a carboxylic acid.