The correct answer is five days.
The Brady Handgun Violence Prevention Act ( Brady Act or Brady Bill), is a U.S. legislation, adopted in 1993. It imposed a five-day waiting period on purchases of guns. During that time, background checks on potential guns owners were conducted to determine their risk of owning a weapon.
This Act was in use until 1998 when a new NICS system of background checks was introduced.
The Bill was named after James Brady, the White House press secretary who was seriously injured in the attempted association of President Ronald Reagan.
The National Rifle Association opposed the Act.