The Speed of Light Is Given by the Value of $\varepsilon$

The speed of light is given by the value of

A) $\varepsilon$ ₀ $\mu$ ₀.
B) $\sqrt { \varepsilon _ { 0 } \mu _ { 0 } }$ .
C) $\frac { 1 } { \sqrt { \varepsilon _ { 0 } \mu _ { 0 } } }$ .
D) $\frac { 1 } { \varepsilon _ { 0 } \mu _ { 0 } }$ .
E) $\sqrt { \frac { \varepsilon _ { 0 } } { \mu _ { 0 } } }$ .