In the Featured Study on perceiving geographical slant, Proffitt and his colleagues (1995) found

A. participants tended to overestimate the slant of 20-degree or steeper hills, while underestimating the slant of hills less than 20-degrees
B. participants tended to underestimate the slant of 20-degree or steeper hills, while overestimating the slant of hills less than 20-degrees
C. verbal and visual estimates of steepness were accurate but haptic estimates tended to overestimate steepness
D. haptic estimates of steepness were accurate but verbal and visual estimates tended to overestimate steepness