Answer:
The superlative to fill in the blank could be:
- <u><em>Carísimo</em></u><em>.</em>
<em>- </em><em>Me encantaría viajar a todas partes del mundo pero no puedo ahora porque es </em><u><em>carísimo</em></u><em>.</em>
Explanation:
The translation of the formed sentence is:
- I would love to travel to all parts of the world but I can't now because it is <u>very expensive</u>.
In the case of this sentence, a type of superlative in Spanish called absolute superlative was used, which regularly has the ending <em>"ísimo"</em> (<u>with emphasis on the first vowel 'i' shown</u>), that termination is added after removing the last letter from the adjective ( if it is a singular adjective) or the last two letters (if it is a plural adjective), such <em>"caro"</em> is a singular adjective, only the last letter is removed and the mentioned termination is added, so the correct absolute superlative is <u><em>"carísimo"</em></u>.