Kids who are between 5 and 12 years old need to sleep this long to feel refreshed and ready to learn the next day:

Question

$\begin{array}{1 1} (a)\; \text{7 to 8 hours} \\ (b)\; \text{8 to 9 hours} \\ (c)\; \text{9 to 10 hours} \\ (d)\; \text{10 to 11 hours} \end{array}$