Answer:
The correct translation to "Ernesto is bringing it" is "Ernesto está trayéndolo".
Step-by-step explanation:
The sentence given is making use of a direct object pronoun. Ernesto is the subject, while the thing he's bringing (that is not clarified in the text) is the direct object. The direct object pronoun is here added to the verb "trayendo" which results in "trayéndolo".
"Ernesto lo está trayendo" could be another example of the use of a direct object pronoun for this case.
Direct object pronouns are used to replace the direct object of a sentence in order to achieve a more cohesive and less redundant phrase.