Joseph has just been hired on to a contractor company of the department of defense

Joseph has just been hired on to a contractor company of the department of defense as their senior security analyst. joseph has been instructed on the company's strict security policies that have been implemented, and the policies that have yet to be put in place. per the department of defense, all dod users and the users of their contractors must use two-factor authentication to access their networks. joseph has been delegated the task of researching and implementing the best two-factor authentication method for his company. joseph's supervisor has told him that they would like to use some type of hardware device in tandem with a security or identifying pin number. joseph's company has already researched using smart cards and all the resources needed to implement them, but found the smart cards to not be cost effective. what type of device should joseph use for two-factor authentication?