Answer
$\rm Perfect \;destructive.$
Work Step by Step
First of all, we need to sketch the problem as seen below.
We need to find what kind of interference is at point $\rm P$.
We know that the two waves are out of phase, so their wavelength is the same and is given by
$$v=\lambda f$$
$$\lambda=\dfrac{v}{f}=\dfrac{3\times 10^8}{3\times 10^6}=\bf 100\;\rm m\tag 1$$
And we know that the path length difference at some point is given by
$$\Delta r=r_2-r_1$$
where $\Delta r=r_2-r_1$ while $r_2=\sqrt{4^2+2^2}$
Now since the two waves are out of phase, then If the path length difference was an integer number of $\lambda$, then the interference is perfectly destructive. And if it was some number of wavelengths and a half, then it is perfectly constructive interference.
$$\Delta r=1000-800=200\;\rm m$$
Thus,
$$\Delta r=\dfrac{200}{100}\lambda=2\lambda$$
So it is perfectly destructive.