Thus, PCC is a complex of chromium trioxide with pyridine and HCl, making option (D) the correct answer.
Pyridinium chlorochromate (PCC) is a reagent formed by reacting chromium trioxide (CrO₃) with pyridine, and often involves the addition of HCl to complete the preparation. PCC is a mild oxidizing agent that selectively oxidizes primary alcohols to aldehydes and secondary alcohols to ketones.