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. electrons are boiled off filament
II) electricity leaves the autotransformer
III) electricity goes to primary side of step-down transformer
IV) filament is heated

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