Which one of the following frequencies of radiation ( in Hz) has a wavelength of 600 nm?

Question

$\begin {array} {1 1} (1)\;2.0 \times 10^{13} & \quad (2)\;5.0 \times 10^{16} \\ (3)\;2.0 \times 10^{14} & \quad (4)\;5.0 \times 10^{14} \end {array}$