(c) Let potential of $P_{1}$ is 0 V and potential of $P_{2}$ is $V_{0}$. Now apply KCL at $P_{2}$.
$\frac{V_{0} - 5}{2} + \frac{V_{0} - 0}{10} + \frac{V_{0} - ( - 2)}{1} = 0$
$\Longrightarrow \ \ \ \ V_{0} = \frac{5}{16}$
So, current through 10$\Omega$ resistor is
$\frac{V_{0}}{10}$ from $P_{2}to\ P_{1}$.