c. less physically fit individuals perceived the hill as being more steep. The 1999 study "Visual-Motor Recalibration in Geographical Slant Perception" by Mukul Bhalla and Dennis R. Proffitt showed the results of 4 experiments. These experiments showed that people who are wearing a heavy backpack, or who are fatigued, or who have low fitness, or who are elderly or unhealthy consistently perceived hills as being steeper than they really are. So with that in mind, let's look at the available options and pick the correct one. a. individual fitness level does not affect perception of hill steepness. * This is in direct conflict with the study, so it's wrong. b. fit individuals perceived hills as being more steep because they were fatigued. * It's true that fatigued people perceive the hills as being steeper, but fatigue isn't an effect of being fit. So this too is a bad choice. c. less physically fit individuals perceived the hill as being more steep. * This agrees precisely with experiment #3 of the paper. So this is the correct choice. d. none of these. * Since choice "c" above has been selected, this is obviously incorrect.