Pete contracts with Betty to buy a mouse trumpet for $$800.$ However, Betty later refuses to perform. Betty had purchased the trumpet for $$600.$ When Betty breaches their contract, Pete finds a gopher trumpet for $$1,100$ and another mouse trumpet for $$1,200,$ which he buys. Pete sues Betty for breach of contract. What measure of damages?

a$.$

$$100$

b$.$

$$200$

c$.$

$$300$

d$.$

$$400$