The first choice is the correct answer. In order to get the answer you see on the graph shown there is the whole numbers 0, 1, and 2. The 2nd, 3rd, and 4th choice is incorrect because the first choice is only counting for 5 days. The 3rd choice is incorrect because it is counting 1 mile for each day, but look at the problem. It says 1/5 mile of the ditch he was digging not 1 whole each day. The same thing is for the 4th choice. The 4th choice is also incorrect because that is also counting 1 mile each day. So the correct answer is the first choice because it follows through the word problem.