| As shown in the illustration, in addition to mechanical interlocking of the contactors, how is simultaneous pulling in of both the "1S" and 'R" contactors prevented? |
| A) Electrical interlocking by means of normally open "1S" and "R" auxiliary contacts. |
| B) Electrical interlocking by means of normally closed "1S" and "R" auxiliary contacts. |
| C) Electrical interlocking by means of the normally closed, timed open and the normally open, timed closed "2S" contacts. |
| D) Mechanical interlocking is the only means by which simultaneous pulling in of the "1S and "R" contactors is prevented. |
