A common location of clear air turbulence is

A. near a ridge aloft on the equatorial side of a high-pressure flow.

B. in an upper trough on the polar side of a jet stream.

C. south of an east/west oriented high-pressure ridge in its dissipating stage.

B. in an upper trough on the polar side of a jet stream.

Explanation:

The clear air turbulence is produce when the object is surrounded by several clouds and the air has different directions and forces around the flying object.

In the jet stream, when the cool air coming from the poles meet the warm air of the ecuatorial part of our planet, the mixing is the result of different air densities, forces and directions, producing a clear air turbulence.