Answer
This process does not proceed via the strong interaction.
Work Step by Step
The $K^0$ has strangeness $+1$
The $\pi^+$ has strangeness $0$
The $\pi^-$ has strangeness $0$
The net strangeness of the left side of the process is $+1$
The net strangeness of the right side of the process is $0$
Since strangeness is not conserved in this process, this process does not proceed via the strong interaction.
