I’m over 21 years of age. I am a citizen of theUnited   States. I have not been convicted of felony. And I have not been treated or confined for drug addiction, drunkenness, or mental illness. According to the National Firearms Act of 1934, I thus qualify to purchase a fully automatic machine gun capable of firing hundreds of bullets with a single squeeze of the trigger. 
A、I'm qualified to purchase a gun.
B、I'm a good citizen.
C、Anyone under 21 can't legally own a gun.
D、Drug addiction may disqualify one to own a gun.