Final answer:
The correct direct object pronoun to complete the sentence is 'lo'.
Step-by-step explanation:
The correct direct object pronoun to complete the sentence “Ana quiere comer el taco” is lo.
In Spanish, the direct object pronoun ‘lo’ is used to replace masculine singular objects. Since ‘taco’ is a masculine singular noun, it is replaced by the pronoun ‘lo’.
For example, the sentence “Ana quiere comer lo” means “Ana wants to eat it.”
Learn more about Direct object pronouns in Spanish