| As shown in the illustrated two speed motor controller, how is simultaneous energization of both contactors prevented? |
| A) electrical interlocking with the normally closed low speed and high speed contactor auxiliary contacts only |
| B) electrical interlocking with the normally closed low speed and high speed start pushbutton contacts only |
| C) mechanical interlocking with the low speed and high speed contactors only |
| D) electrical interlocking with the normally closed low speed and high speed contactor auxiliary contacts and the normally closed low speed and high speed start pushbutton contacts |
