Let  $\nabla .(fv)=x^2y+y^2z+z^2x$ , where $f$ and $v$ are scalar and vector fields respectively. If $v=yi+zj+xk$ then $v.\Delta f$ is
1. $x^2y+y^2z+z^2x$
2. $2xy+2yz+2zx$
3. $x+y+z$
4. $0$