Final answer:
Option C, which describes the oxidation of hydroquinone to quinone while producing hydrogen atoms that can inhibit radical propagation, correctly shows how hydroquinone inhibits radical propagation in a reaction.
Step-by-step explanation:
The question is asking which reaction correctly shows how hydroquinone inhibits radical propagation. Among the given options, option C: 2C6H4(OH)2 → 2C6H4O + 2H2 represents the oxidation of hydroquinone to quinone while giving up hydrogen atoms. These hydrogen atoms can combine with free radicals, thereby inhibiting the propagation of radical chain reactions. The other options do not involve hydroquinone and hence do not represent the inhibition process by hydroquinone.