Wire rope

It is 6x36 which most suitable for winding on the drums. size depends on the load you would like to lift. Also minimum dia of the drum is selected by multiplying the rope dia x 24. For example:-You have to lift load of 1000kg. You need to maintain factor of safety as 5, then break load of wire rope should be minimum 5000kgs. If you find wire rope of 7mm dia and 6x36 construction and having break load of 5000kgs then your drum dia should be minimum 7x24=168mm. Also core can be fiber or steel depending on the application. For general purpose fiber core is used for use over furnace steel core is used.

The first digit is the number of strands in the wire and the second is the number of wires in the strand the smaller the wire the more flexible the cable. But before i would recommend and wire for a drum size I would check the manufactures specs for minimum turning radius.

You don't give enough information to answer the question. What sort of core? Which material? Size? Why these 4 choices? There are some good choices in between that you don't consider.

And, are you the sort of person who would saddle a dead horse?