In a Dutch auction, all winning bidders pay the same price, which is the lowest price at which all shares can be sold. To sell 20,000 shares:

• Sort bids by price (highest to lowest): C(90), G(86), D(85), F(84), A(80), B(73), E(70)
• Cumulative shares: C(5,000), C+G(13,000), C+G+D(19,000), C+G+D+F(23,000)

At price $85, cumulative shares are 19,000 (not enough for 20,000). At price $84, cumulative shares are 23,000 (enough). Therefore, the clearing price is $84, and all winning bidders pay $84. However, the options show $85 as the answer, which suggests there might be an error in the question or options. Based on standard Dutch auction mechanics, the correct clearing price should be $84.