75. 下列四種物質的硬度大小: (1)瓷 (porcelain) (2)汞齊 (amalgam) (3)硬黃金合金 (hard gold alloys) (4)牙骨質(cementum) 請問其硬度由大而小的排序應該是:(A) (2)>(1)>(3)>(4)(B) (1)>(2) >(3)>(4)(C) (1)>(3)>(2)>(4)(D) (1)>(2)>(4)>(3)