In which of the below cases would winds be closest to geostrophic balance?
a. in meridional flow at the surface near the equator.
b. at the surface in the eyewall of a hurricane.
c. in zonal flow at the surface near the equator.
d. in zonal flow, just above the pbl, near 50°n

C. In zonal flow at the surface near the Equator

Explanation:

As these winds have a problem with the Coriolis force that is the rotation of the earth on its axis. Occurring in mid-latitudes aloft the air currents. This balance does not occur near the surface since the friction force is significant. The geostrophic winds develop in a well-defined layer of air i.e either hot or cold. In a geostrophic flow of water bodies instead of the winds moving from high to low pressure, due to the rotation of the earth. The major current sin the ocean like Gulf stream and Kuroshio, and Agulhas current are all approximation and examples of geostrophic current.