The elevations, in feet, of three cities are marked on the number line shown below.
The point 0 on the number line represents sea level. Which statement must be true?
A
City P and City Q are above sea level.
B
City Q and City R are below sea level.
C
City P is above sea level and City Q is below sea level.
D
City P is above sea level and City R is below sea level.