I believe the answer is A.
The other values have repeated X values.
The Area of a piece of paper
17x +x to the second power
Answer; c^2 = a^2 + b^2
c = 17 inches
a = 8 inches
b^2 = c^2 – a^2
b^2 = 17^2 – 8^2
b^2 = 289 – 64
b^2 = 225
b = square root of 225
b = 15 inches ≈ c.