Answer: Hello mate!
Here we have a graph with 4 pairs in it:
(0,0), (1,4), (2,8), (3,12)
where the x-axis is the amount of peanuts bags, and the y-axis is the price.
Now you want to know hat is the price of one bag of peanuts.
You can see on the pair (1,4), that when x = 1 (one bag), y is equal to 4 (4 dollars)
so the price of one bag of peanuts is 4 dollars, then the correct option is the second one; $4.
And so on, the price of two bags is $8, the price of 3 bags is $12, etc.