Which man announced his resignation as U.S. secretary of defense in December 1993?

Circus Oz, a satirical circus that turned 21 in 1999, comes from which country nicknamed "Oz"? In 1991 former Soviet republics formed the CIS, the Commonwealth of what? Which leader divorced his wife Winnie in 1996? In 1990 Citgo became wholly owned by the state oil company of which country? Which U.S. ICBM, named for Revolutionary War citizen soldiers, was first deployed in 1962? Citrine is a yellow variety of which mineral? Which city was known until 1860 as West Urbana? Which Ohio city is associated with Firestone, Goodrich and Goodyear?