Answer:
Oxygen bleach is hydrogen peroxide with sodium and sometimes sodium carbonate (washing soda) added. Oxygen bleach is a gentler and less toxic alternative to chlorine bleach, so it can be used on all sorts of washable fabrics.
Chlorine bleach is much stronger than oxygen bleach, but it is not good for every fabric and has a very harsh smell.
Explanation:
A. Would be the answer I chose.
It said one of the following WORKOUT CHANGES, so I'm assuming that it doesn't want you to just stop. Different shoes may provide better support, bringing relief to the knees and allowing you to continue your walking workout.
