Correct option is D
Solution:

Analyze the options:
Option (a): "Vorticity is a null vector for all finite x, y, z"
This is incorrect because the curl is not zero.Option (b): "Vorticity is parallel to the vector field everywhere"
This is incorrect because the curl of a vector field is always perpendicular to the original vector field.Option (c): "The angle between vorticity and vector field depends on x, y, z"
This is incorrect because the angle between the curl and the original field is always 90 degrees.Option (d): "Vorticity is perpendicular to the vector field everywhere"
This is correct because the vorticity vector is always perpendicular to the original vector field for this calculation.




