Which of the following is an irrotational vector field?
⟨y,−x,0⟩\langle y, -x, 0 \rangle⟨y,−x,0⟩
⟨z,x,y⟩\langle z, x, y \rangle⟨z,x,y⟩
⟨ex,siny,z2⟩\langle e^x, \sin y, z^2 \rangle⟨ex,siny,z2⟩
⟨x2,y2,z2⟩\langle x^2, y^2, z^2 \rangle⟨x2,y2,z2⟩