The inputs used to produce cupcakes (e.g., flour, sugar, butter, and labor) are also used to produce cookies, cakes, muffins, pies and many other goods. This suggests that:

A、the elasticity of supply of cupcakes is relatively high.;

B、cupcakes are a normal good.;

C、the elasticity of supply of cupcakes is relatively low.;

D、the supply curve for cupcakes is downward sloping.