Definition: Write a correct answer for the question. You should reason about prototypical situations and provide the correct answer. Avoid answers that provide incomplete justification for the question.

Positive Example 1 -
Input: at the beach, name something that might protect you from sun.
Output: umbrella

Positive Example 2 -
Input: after a week of camping, what luxury at home are you most excited to have again?
Output: bed

Negative Example 1 -
Input: at the beach, name something that might protect you from sun
Output: water

Negative Example 2 -
Input: after a week of camping, what luxury oh home are you most excited to have again?
Output: tent

Now complete the following example -
Input: name a source of energy people used before oil:

Output: coal, wood, water, wind, steam