Which of the following describes a major difference between parallel lines and perpendicular lines?
a. Parallel lines intersect at either obtuse or acute angles, and perpendicular lines intersect at right angles.
b. Parallel lines intersect, and perpendicular lines do not intersect.
c. Parallel lines do not intersect, and perpendicular intersect.
d. Parallel lines intersect at right angles, and perpendicular lines intersect at either obtuse or acute angles.