Your answer is A) 1 teaspoon.
The ratio for this problem is 8, 2, where 8 is the people, and 2 is the teaspoons. 4 people is half of 8 when you divide 8/4 so you have to do the same with the other part of the ratio. when you split 2 in half, you get 1 teaspoon as your answer
Hope this helps :)
