Consumer porcelains in Jingdezhen are not selling well in export market as compared with those made in Liling, Hunan Province and Zibo, Shandong Province.

A．on export market

B．in exporting market

C．in exported market

D．in the export market

试简述数字显示仪表与模拟显示仪表相比时的优点和缺点。