$R= \left \{\left (x, y \right) | 1 \leq xy \leq 4, 0 < x \leq y \leq 4x \right.$ 일 때, $\displaystyle \iint _ {R} ^ {} {\frac{y} {x}} dA$ 의 값은?

• ①$\displaystyle \frac{9} {2}$
• ②$3$
• ③$\displaystyle \frac{9} {4}$
• ④$\displaystyle \frac{9} {5}$
• ⑤$\displaystyle \frac{3} {2}$