The suggestion of the meeting __________was not adopted by the chairman, so the meeting would be held on time.

A．to put off

B．putting off

C．put off

D．being put off

2012年8月内，某市市区一周空气质量报告中其气体污染指数的数据是：37，39，38，37，39，42，36，这组数据的中位数是______．