问题如下：
Which factor can improve pricing power?
选项：
A.Market share volatility.
B.Market concentration.
C.Unused productivity.
解释：
B is correct.
A high level of concertration typically decreases market competitive power and results in greater power of pricing. In an industry with greater unused productivity, its pricing power reduces and price competition increases. Power of pricing increases along with greater stability in market share.
不对啊，不是说了不一定么
