A Seller Contracts to Sell Some Rare Coins to a Collector

A seller contracts to sell some rare coins to a collector for $10,000,to be delivered 2 months after the date of the contract.On the date that delivery is due,the coins are worth $12,000,but the seller refuses to deliver.The collector acquires similar coins the following week for $13,000,the best price he can find.What can the collector recover from the seller?

A) $1,000
B) $2,000
C) $3,000
D) $5,000
E) Nothing,because she chose to enter into a separate contract for the purchase of coins from another seller.