First. Immediately to raise, organize, officer, and equip all or such number of increments of the Regular Army provided by the national defense Act approved June third, nineteen hundred and sixteen, or such parts thereof as he may deem necessary; to raise all organizations of the Regular Army, . . . to the maximum enlisted strength authorized by law. . . . Second. To draft into the military service of the United States, organize, and officer, . . . any or all members of the National Guard and of the National Guard Reserves, and said members so drafted into the military service of the United States shall serve therein for the period of the existing emergency unless sooner discharged.

–Selective Service Act of 1917

How were members of the National Guard affected by this legislation?

They were formed into a new organization.
They were immediately discharged from service.
They were drafted for the entire term of the emergency.
They were disallowed from becoming members of the military.