49. What does the author mean by “misperception of slope steepness only happened at the chance level” for participants assigned to the escalator group?
(A) Misperception of slant is consistently observed.
(B) The occurrence of misconception is not observed.
(C) The slope steepness is estimated in a biased and unfair way.
(D) The tendency to overestimate a slant cannot be consistently obtained.