1975 was the last year Chevrolet offered a convertible Corvette for the C3. What year did the convertible option return?

After an 11 year hiatus, a new Corvette convertible is introduced in 1986. The 1986 Corvette also paced the Indianapolis 500, and all convertibles were designated as pace car replicas regardless of color or option content, and all included decal packages for dealer or customer installation. The actual Indy Pace Car was yellow and 732 yellow convertibles were sold for the model year. A total count of 7,315 convertibles were built in 1986 with a base sticker price $32,032.00.
Source: Corvette Black Book