Final answer:
The correct pronoun to replace the direct object is 'La'.
Step-by-step explanation:
To replace the direct object in the sentence 'Manuel delega las responsabilidades a los voluntarios en el hogar de ancianos,' we need to use the direct object pronoun that corresponds to 'responsabilidades' which means 'responsibilities.' Since 'responsabilidades' is a feminine noun, we would use the pronoun 'las' which corresponds to 'them' in English.
So, the correct pronoun to replace the direct object is La.
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