Figure shows the results of an experiment involving photoelectric effect. The graphs A,B,C,D relate to light beams having different wavelengths.

Question

$\begin {array} {1 1} (a)\;Beam \: B\: has\: highest\: frequency & \quad (b)\;Beam\: C\: has\: longer \: wavelength \\ (c)\;All\: of\: these & \quad (d)\;Beam\: A\: has\: highest\: rate\: of \: photoelectron\: emission. \end {array}$