The third alternative is correct (C).
Problems of mobility in people vary according to the degree of impairment of the person's motor ability, which in turn may vary according to the cause that has compromised that person's mobility. People may be born with disabilities, they may be injured or their motor capacity may decrease due to age or overweight.
In this context, people use locomotion assistance tools according to their needs and wants. Some use walking sticks, walkers and others need a wheelchair.
