The figure shows the variation of photocurrent with anode potential for a photo-sensitive surface for three different radiations. Let \[{{I}_{a}},\ {{I}_{b}}\]and \[{{I}_{c}}\] be the intensities and \[{{f}_{a}},\ {{f}_{b}}\] and \[{{f}_{c}}\] be the frequencies for the curves a, b and c respectively [IIT-JEE (Screening) 2004]

• A.            \[{{f}_{a}}={{f}_{b}}\] and \[{{l}_{a}}\ne {{l}_{b}}\]
• B.            \[{{f}_{a}}={{f}_{c}}\] and \[{{l}_{a}}={{l}_{c}}\]
• C.            \[{{f}_{a}}={{f}_{b}}\] and \[{{l}_{a}}={{l}_{b}}\]
• D.            \[{{f}_{a}}={{f}_{b}}\] and \[{{l}_{a}}={{l}_{b}}\]