Consider an auction in which there are two bidders who are both risk-neutral. Each have private valuations of the item being sold, denoted by t1 and t2 respectively. For example, if Bidder 1's private valuation is $100, then we write t1=100. The bids in the auction are denoted a, and a2. For example, if Bidder 1 bids $75, then we write a1=75. [In the language of Bayesian game theory, t1 is player 1's type, and a, is her action.] For each of the auction types listed, identify the correct utility function, u1, for Bidder 1. (The answers are listed in a random order.) A Sealed Bid First-Price Auction A. u1 = t1 - a1 where a1>a2 0.5(t1 - a1) where a1=a2 A Sealed Bid Second-Price Auction O where a1a2 An All-Pay Auction 0.5t1 - a1 where a1=a2 where a1a2 0.5(t1 - a2) where a1-a2 O where a1a2 0.5t1 where a1=a2 where a1