Which word is best related to the underlined word in the paragraph and how do the words relate?

dave went for a day hike in the woods with only a bottle of water and a few granola bars. when he didn’t return home after two days, his family was worried. rescuers were sent out searching for him. food and water is )) to our survival. the human body can exist without food for up to three weeks, but we can survive without water for only three days.

a.
required

both describe that we need food and water to live.

b.
unprepared

both describe dave's situation in the woods.

c.
locate

both describe the purpose of the rescuers.

d.
concerned

both describe how dave’s family felt about him.