Answer
See the detailed answer below.
Work Step by Step
$$\color{blue}{\bf [a]}$$
As we explained in the previous problems, according to classical mechanics, there will be no change in the graph since the intensity of the light remains constant. It has no relation to the wavelength of the light or its frequency.
Thus, the original given graph remains constant according to classical physics.
$$\color{blue}{\bf [b]}$$
According to classical mechanics, a metal with a smaller work function - with the same light intensity- would produce electrons with higher kinetic energy since we know that $K_{max}=E_e- E_0$.
This means that the emitted electrons will need a higher stopping potential energy. Thus the curve will shift to the left from the left side, as shown in the second figure below.
