A set of parallel runways labeled as 36L and 36R from the north would be labeled as what from the opposite end?

The correct labeling for parallel runways is determined based on their magnetic heading. Runways are numbered according to their compass bearing rounded to the nearest ten degrees, and labels are assigned such that runways aligned in the same direction will have numbers that are oppositely correlated when viewed from opposite ends.

In this instance, runways labeled as 36L and 36R indicate that they are oriented towards a magnetic heading of approximately 360 degrees. When viewed from the opposite end, which would be the south end of these runways, the appropriate magnetic heading will be 180 degrees. Therefore, the new identification will be 18L and 18R. This reflects the correct conversion from runways 36L and 36R when viewed from the opposite direction.

Thus, the correct labeling for 36L and 36R when approached from the opposite end is indeed 18L and 18R, not any of the other options listed. Each of the other choices reflects numerical headings that do not correspond to the mentioned magnetic bearing of the runways in question.