Final answer:
The method used to correct the ambiguous pronoun reference in the sentence is to repeat the antecedent and place the pronoun nearer the antecedent. Option D.
Step-by-step explanation:
The method used to correct the ambiguous pronoun reference in the revised sentence is D. The antecedent was repeated. The pronoun was placed nearer the antecedent.
By repeating the antecedent 'Roger' before the pronoun 'he', the sentence becomes clearer and reduces ambiguity. This allows the reader to understand that it is Roger who had to work on Monday.
Here's the revised sentence: Roger told David that Roger himself had to work Monday.
So option D is correct.