One victory of the clinton administration was a. clinton's impeachment. b. clinton's health-care initiative. c. the contract with america. d. the passage of the brady bill.

The correct answer here is D.
The passage of the Brady Bill, that is the Brady Handgun Violence Prevention Act, which was passed in 1993. The bill mandated background checks before a weapon could be purchased and and five day waiting period until  1998 when NICS system was implemented. The bill was named after James Brady who was shot during the assassination attempt on the president Ronald Regen.