Task: Class Definition Understanding (ontology: Earth_Environment/SWEET)

Which of the following definitions best describes 'point vortex'?

A. A the concept event occurs whenever plates drift apart (Plate Divergence). [Wikipedia]
B. Mesoscale vortices observed at the ends of a line segment of convective cells, usually cyclonic on the northern end of the system and anticyclonic on the southern end, for an environment of westerly vertical wind shear
C. The net slip of the fault (slip vector) is parallel to the strike of the fault.
D. A straight line vortex, the flow of which can be modeled in two dimensions, with a point concentration of vorticity surrounded by irrotational flow.

Answer: A straight line vortex, the flow of which can be modeled in two dimensions, with a point concentration of vorticity surrounded by irrotational flow.