The No$-$additional$-$cost services exclusion applies to a service the employer provides to an employee if it does not cause the employer to incur any substantial additional costs. No$-$additional$-$cost services are excess capacity services that include all of the following except:

A$.$ Train tickets provided free

B$.$ Facilitation by a stock brokerage firm of the purchase of stock by employees

C$.$ Hotel rooms provided free

D$.$ Telephone services provided free