A graph of volume of hydrogen released vs time for the reaction between zinc and dil. HCl is given in the graph below.
                         
The correct statement among the following based on the graph given above is:

$$\begin{gathered} 1.<mspace\; width="1em"></mspace>\mathrm{Average}<mspace\; width="1em"></mspace>\mathrm{rate}<mspace\; width="1em"></mspace>\mathrm{upto}<mspace\; width="1em"></mspace>40s\text{\hspace{0.17em}is\hspace{0.17em}}\frac{V_3-V_2}{40} \\ 2.<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>\mathrm{Average}<mspace\; width="1em"></mspace>\mathrm{rate}<mspace\; width="1em"></mspace>\mathrm{upto}<mspace\; width="1em"></mspace>40s\text{\hspace{0.17em}is\hspace{0.17em}}\frac{V_3-V_2}{40-30} \\ 3.<mspace\; width="1em"></mspace>\mathrm{Average}<mspace\; width="1em"></mspace>\mathrm{rate}<mspace\; width="1em"></mspace>\mathrm{upto}<mspace\; width="1em"></mspace>40s\text{\hspace{0.17em}is\hspace{0.17em}}\frac{V_3}{40} \\ 4.<mspace\; width="1em"></mspace>\mathrm{Average}<mspace\; width="1em"></mspace>\mathrm{rate}<mspace\; width="1em"></mspace>\mathrm{upto}<mspace\; width="1em"></mspace>40s\text{\hspace{0.17em}is\hspace{0.17em}}\frac{V_3-V_1}{40-20} \end{gathered}$$