The answer is in d) above. ATC ensure that divergence is assured. We do it here by issuing headings.
For example: Say you have runways 36L/C/R with a strong wind from the NW. If traffic from 36L normally flies 345', 36C flies 360' and 36R 015', you may need to use 340', 355' and leave 36R as 015'. If the wind is stronger just use more correction: 335', 350' and 015'. We normally leave the "downwind" runway uncorrected.
You can't just leave them uncorrected and some aircraft may not be able to fly tracks. There is no weather criteria or minima, its just a case of ATC noticing or more likely anticipating that divergence may not be assured and doing something to assure it.
Hope that helps.