The divergence of a vector field F\mathbf{F}F is defined by which operator?
∇×F\nabla \times \mathbf{F}∇×F
∇⋅F\nabla \cdot \mathbf{F}∇⋅F
∇F\nabla F∇F
∂F∂x\frac{\partial F}{\partial x}∂x∂F