This reaction involves the esterification process, where phenol (\( \text{C}_6\text{H}_5\text{OH} \)) reacts with benzoic acid (\( \text{C}_6\text{H}_4\text{COOH} \)) in the presence of an acid catalyst (H\(^+\)) and excess NaOH to form an ester. However, esterification is not shown explicitly in this reaction. The presence of excess NaOH indicates the formation of a salt or sodium phenoxide due to the deprotonation of phenol in the basic medium. The final compound B formed will be colourless, as no coloured intermediate or product is involved in this esterification-like reaction. Thus, the correct answer is colourless. (C) Colourless.