Answer:
The correct word to complet the answer is:
-Será.
- Carlos: ¡Será maravilloso ir aquí!
Explanation:
The conversation between Manuel and Carlos is about a future trip.
Manuel asks Carlos what he thinks to go a ecoturistic place.
The key is to look for the correct verb and tense.
The verb is: Be
Be in future tense is will be.
