A bakery sells cakes in three different sizes: small ($S$), medium ($M$), and large ($L$). The medium size costs $40\textbackslash\%$ more than the small size and contains $25\textbackslash\%$ less cake than the large size. The large size contains twice as much cake as the small size and costs $60\textbackslash\%$ more than the medium size. Rank the three sizes from best to worst buy in terms of cost per unit of cake. (Adapted From 2005 AMC 8 Problems, Question \#22) 
选项为:A:$MSL$  B:$SML$  C:$LSM$  D:$SLM$  请回答其中一个选项.