(Please explain the correct answer-- I picked letter A)
 The highest surface wind speeds occur when there is a:
 A) 4 millibar air pressure difference between 2 nearby locations
 B) 4 millibar air pressure difference between 2 distant locations
 C) 20 millibar air pressure difference between 2 nearby locations
 D) 20 millibar air pressure difference between 2 distant locations