How does the presence of angled lines positioned at both ends of a straight line influence
the interpreted length of the straight line?

a. inward-facing angled lines make the straight line appear to be longer than it actually is.

b. outward-facing angled lines make the straight line appear to be longer than it actually is.
c. outward-facing angled lines make the straight line appear to be shorter than it
actually is.
d. angles up to 7 degrees cause the müller-lyer illusion to occur; after that, the angle has
almost no influence.