Electromagnetic Radiation Can Be Specified by Its Wavelength $\lambda$ ), Its Frequency (V) or Its Period

Electromagnetic radiation can be specified by its wavelength ( $\lambda$ ) , its frequency (v) or its period ( $\tau$ ) . The period $\tau$ is the time it takes one complete wavelength to pass a point in space. Based on this information, what is the mathematical relationship between v and $\tau$ ?

A) (v = 1/ $\tau$ )
B) (v = $\tau$ )
C) ( $\tau$ = v/c)
D) c = $\tau$ x v
E) ( $\tau$ = c/v)