Answer:
Geostrophic wind D) flows parallel to contour lines of upper-air pressure .
Explanation:
Geostrophic wind -
Air parcel generally moves from higher pressure to lower pressure due to pressure gradient force and left or right deflection due to coriolis force. When this deflection takes place a time comes when pressure gradient force and coriolis force becomes equal and the air parcel moves parallel to isobar then the winds are called geostrophic winds .