Walking is not the most exciting form of exercise a person can take on for fitness. Yet it is low impact and requires no fancy equipment. That makes walking a simple activity for those new to exercise. Walking is less likely than other exercises to cause injury to leg tendons and muscles. All it requires is a good pair of sneakers—no cables, stylish outfits, or weights required. Of course, a person could increase the benefit of a workout by adding weights or speed walking. How does the third sentence ("That makes walking...") support the main idea of the paragraph? (5 points)

a
It points out that walking is a good introduction to exercise for beginners.
b
It says that walking is too easy for people who have experience with exercise.
c
It points out that beginning exercisers may not like walking because it is too easy.
d
It says that walking is less costly than other activities because it needs no equipment.