Death Valley has an altitude that is below sea level. Which situation describes a hiker in Death Valley who hikes until he reaches an altitude of 0 feet? A - The hiker starts at 0 feet then decreases their altitude by 10 feet.
B - The hiker starts at -10 feet then decreases their altitude by 10 feet.
C - The hiker starts at 10 feet then increases their altitude by 10 feet.
D - The hiker starts at -10 feet then increases their altitude by 10 feet.