How many perfect squares lie between 120 and 300 ?

Answer: Option C

$$\begin{array}{rl}& {\left(11\right)}^2=121\\ & \text{And }\\ & {\left(17\right)}^2=289\end{array}$$
So, the perfect squares between 120 and 300 are the squares of numbers from 11 to 17.
Clearly, these are 7 in number.