Solution (source code)

= Solution

By <multiplication of a distribution by a smooth function>, for every <test function> $\psi$,
$$
\langle\rho\delta_0,\psi\rangle
=\langle\delta_0,\rho\psi\rangle
=\rho(0)\psi(0)=\psi(0)
=\langle\delta_0,\psi\rangle.
$$
Hence $\rho\delta_0=\delta_0$.