Emily can solve $5$ questions in $6$ minutes while Megan can solve $7$ questions in $24$ minutes. What is the efficiency ratio of Emily to Megan ?

A. $\displaystyle \frac{20}{7}$

B. $\displaystyle \frac{5}{7}$

C. $\displaystyle \frac{7}{20}$

D. $\displaystyle \frac{28}{5}$

E. $\displaystyle \frac{7}{5}$

A. $\displaystyle \frac{20}{7}$

B. $\displaystyle \frac{5}{7}$

C. $\displaystyle \frac{7}{20}$

D. $\displaystyle \frac{28}{5}$

E. $\displaystyle \frac{7}{5}$