Under crossed polars, a mineral remains dark at all stages of rotation of the microscope stage. Which of the following statement(s) is/are NOT correct? (A) The mineral is isotropic. (B) The mineral is biaxial with an optic orientation corresponding to the principal section of the indicatrix. (C) The mineral is biaxial with an optic orientation containing the Y-vibration direction only. (D) The mineral is uniaxial with an orientation perpendicular to the optic axis.