The answer is B. If you take the even root of a positive number, you'll get two solutions, a positive and a negative
3:1 ratio meaning for every 3 brown eyed people there are 1 blue eyed. So if you have 12 brown every you have 4 blue eyed. Giving you a total of 16 people.
Just go to were the line intercepts the y axis so -2 and rise over run so 2 up and 2 over but its negative so C should be correct.