Roughly What Depth of Flowing Stream Is Dangerous to Drive

Multiple Choice

Roughly what depth of flowing stream is dangerous to drive through?

A) 10 cm (4 inches)
B) 30 cm (1 foot)
C) 60 cm (2 feet) , since water would then be over the axles
D) 120 cm (4 feet) , since water would then be window-height
E) 180 cm (6 feet) , since water would then be above the roof of the car