单选题 角膜曲率测定值分别为8.036/42.006@180和7.966/42.37@90，角膜散光为0.37D，首片试戴片选择曲率半径值为(    )或曲率焦度值为41.75D
   A．8.036mm  B．7.986mm  C．8.086mm  D．8.136mm