In what order should the following sextant adjustments be made? I. Make telescope parallel to frame of sextant. II. Set horizon glass perpendicular to frame of sextant. III. Make index mirror and horizon glass parallel when index arm is set at zero. IV. Set index mirror perpendicular to frame of sextant.

Correct Answer: Option B — IV, II, III, I

Standard marine sextant adjustments must follow a strict optical sequence to avoid disturbing prior calibrations: first make index mirror perpendicular to frame (IV), then horizon glass perpendicular (II), make index and horizon mirrors parallel at zero (III), and finally align telescope parallel to frame (I).