Place the Following Events Leading to the Production of X-Rays

Multiple Choice

Place the following events leading to the production of x-rays in order, from first to last I. alternating current is converted to direct current
II) voltage is adjusted at the autotransformer
III) kilovoltage leaves the step-up transformer
IV) voltage goes to primary side of step-up transformer

A) I, II, III, IV
B) II, I, IV, III
C) IV, III, II, I
D) II, IV, III, I