If sin31° = x/y , then the value of sec31° - sin59° is?

Answer: Option B

sin31° = $$\frac{x}{y}\text{,}$$
∴ sec31° - sin59°
$$\begin{array}{rl}& =\frac{y}{\sqrt{y^2-x^2}}-\frac{\sqrt{y^2-x^2}}{y}\\ & =\frac{y^2-(y^2-x^2)}{y\sqrt{y^2-x^2}}\\ & =\frac{x^2}{y\sqrt{y^2-x^2}}\end{array}$$