Which of these sentences contains a subordinate clause?

a) crimson silk was joanna's choice for her prom dress.
b) hand me the jars with the bright green labels.
c) lisa bought three cds and one poster at the music store.
d) we'll have pizza for supper tonight if we can get home before the store closes.

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. identify the main idea of this paragraph. walking is a difficult and safe exercise for beginners. walking is an easy and safe exercise for beginners. walking is a boring and dangerous form of exercise. walking is an exciting and very effective form of exercise.