问题如下图：
选项：
A. 
B. 
C. 
解释：
麻烦老师解释一下C选项
High barriers to entry. Short letimes to builnew plants. C is correct. High barriers to entry anhigh instry concentration will prohigher returns on capitfor instry. Instry capacity crapiy increaseto satisfy manwith short letimes, however, it malso leto overcapacity anlower profits.c不太明白？神马意思
麻烦老师，我选的A
