Answer:
B. market concentration
Step-by-step explanation:
The answer is that greater pricing power is most likely to result from greater market concentration because this means that there are few competitors in the market which allows to have more power to establish prices.
The other options are not right because unused capacity indicates that there is a lot of competition in the market which doesn't allow to have the power to establish prices and volatility in market share means that there is not a firm position in the market that allows to have greater pricing power.