John is traveling north at 20 meters/second and his friend Betty is traveling south at 20 meters/second. If north is the positive direction, what are John and Betty's speeds?
A.
-20 meters/second, 20 meters/second
B.
20 meters/second, -20 meters/second
C.
-20 meters/second, -20 meters/second
D.
0 meters/second, 40 meters/second