Photoelectric effect experiments are performed using three different metal plates p,q and r having work functions ϕp=2.0 eV,ϕq=2.5 eV and ϕr=3.0 eV, respectively. A light beam containing wavelengths of 550 nm, 450 nm and 350 nm with equal intensties illuminates each of the plates. The correct I-V graph for the experiment is (IIT-JEE-2009)