Answer:
B) Essential
Explanation:
We can start defining the meaning of essential, as a ¨something very important or necessary¨, so having or not having an aspect considered essential for ourselves, it will have an enormous impact in our lives.
The campaign trip is made outdoors, where we need to be more careful with our surroundings (like weather or territory conditions, animals, unwanted people, etc) so it will be<em> essential</em> for the welfare and good experience of the camper to bring to the trip the items asked.
For the sentence context, we can link and relate in a more appropriate way <em>Essential</em> to<em> Critical</em>, due to the considerable importance of the requisites to apply, in order to have a safe and successful campaign trip.