If the imaginary axis length of hyperbola $C$ is $\sqrt{7}$ times the real axis length, then the eccentricity of $C$ is A. $\sqrt{2}$ B. $2$ C. $\sqrt{7}$ D. $2\sqrt{2}$
If the imaginary axis length of hyperbola $C$ is $\sqrt{7}$ times the real axis length, then the eccentricity of $C$ is\\
A. $\sqrt{2}$\\
B. $2$\\
C. $\sqrt{7}$\\
D. $2\sqrt{2}$