21. Cooper and her colleagues argue that a “town of culture” award could_______

答案：[C] increase the economic strength of Britain’s towns.

解析：根据题干中的“Cooper and her colleagues”以“‘town of culture’ award”可定位至第一段。根据第一段最后一句“A town of culture award could, it is argued, become an annual event, attracting funding and creating jobs”可知，这个奖项将吸引投资，创造就业岗位，也就是会提升小镇的经济实力，故C选项为正确答案。