Answer is A, y us smaller/equal to 2 and y is smaller/equal to X
If

, then angle

is obtuse and triangle with sides a, b, c is obtuse triangle.
In an arbitrary triangle can be only one obtuse angle, and the side which lies opposite to the largest angle is the largest. Then since <span>angle

is opposite the side of length a</span> you can conclude that a>c and a>b.
Your answer is c, common sense
<span>1, 4, 9, 16, and 25. Use the formula to get a2 = 1 + (2*2 - 1) = 4, a3 = 4 + (2*3 - 1) = 9, etc. Also notice that for all n, an = n2.</span>