Yes, The main benefit of nitrogen-filled tires is that the loss of tire pressure is slower, because the gas in the tire escapes more slowly than air does. On existing tires, you'll pay up to $30 per tire for service to drain air and refill with N2.
THe answer is A. Themselves. A reflexive pronoun indicates that the person who is realizing the action of the verb is also the recipient of the action.
