The sentence that provides the best evidence to support the underlined statement is:
A. For example, they can be trained to retrieve items, open and close doors, turn lights or appliances on and off, tug socks and shoes off, hand money to the store clerk, call 911, and much more.
This sentence effectively illustrates the specific tasks that mobility dogs can perform to assist individuals with mobility impairments, thus reinforcing the statement about their role in helping those who have difficulty moving.