A laser is a coherent source because it contains:

Question

$\begin {array} {1 1} (a)\;Many\: wavelengths \\ (b)\;Uncoordinated\: wave\: of\: a\: particular\: wavelength \\ (c)\;Coordinated\: wave\: of \: many\: wavelengths \\ (d)\;Coordinated\: waves\: of\: a\: particular\: wavelength \end {array}$