x 3 or 4 for they are the same in terms of function and wiring.

The box without the slash, wired across the coil is drawn as a generic 'snubber',
so for an AC control voltage it would be a capacitor and resister in series
and for a DC control circuit it would usually be a diode wired in 'reverse'.

NB - Many use the term 'snubber' for the AC circuit only.

For a DC coil you could use a resistor but it would increase the background load on the controlling device which would be something that is generally avoided.

In an industrial setting, if there is no snubber circuit drawn you would wire one in externally, although if the coil were small and you were driving it with a transistor you would not bother.

Cheers Glen