The correct answer is $\boxed{\text{C}}$.
The triple integral $\iiint {\nabla \cdot {\text{Pdv}}}$ is the divergence theorem, which states that the integral of the divergence of a vector field over a closed surface is equal to the integral of the vector field over the surface’s boundary.
The line integral $\oint {{\text{P}} \cdot {\text{d}}l}$ is the circulation of a vector field around a closed loop.
The line integral $\oint {\nabla \times \nabla \times {\text{P}}} \cdot {\text{d}}l$ is the curl of a vector field around a closed loop.
The curl of a vector field is a measure of how much the vector field rotates around a point. The curl of a vector field is zero if the vector field does not rotate around a point.
The divergence of a vector field is a measure of how much the vector field spreads out from a point. The divergence of a vector field is zero if the vector field does not spread out from a point.
In this case, the vector field $P$ is not specified, so we cannot determine whether the integral is the divergence theorem, the circulation of a vector field, or the curl of a vector field. However, we can determine that the integral is not the triple integral $\iiint {\nabla \cdot {\text{Pdv}}}$, because the triple integral is only valid for closed surfaces, and the surface in this case is not closed.