Detailed Instructions: Use a disfluent question or a proper question and find the answer to the question based on the given context or return None if an answer can't be found. A disfluent question is a question that has some interruptions in it while framing. A proper question is the correct form of the question without any disfluency.
Q: proper question: What forces shouldn't serve as a brake on wealth concentration?
disfluent question: What forces shouldn't serve as a brake on productivity, no, on wealth concentration?
context: Economist Joseph Stiglitz argues that rather than explaining concentrations of wealth and income, market forces should serve as a brake on such concentration, which may better be explained by the non-market force known as rent-seeking. While the market will bid up compensation for rare and desired skills to reward wealth creation, greater productivity, etc., it will also prevent successful entrepreneurs from earning excess profits by fostering competition to cut prices, profits and large compensation. A better explainer of growing inequality, according to Stiglitz, is the use of political power generated by wealth by certain groups to shape government policies financially beneficial to them. This process, known to economists as rent-seeking, brings income not from creation of wealth but from grabbing a larger share of the wealth that would otherwise have been produced without their effort
A:
None