Final answer:
The Hobbiton Movie Set was left with 39 Hobbit hole facades after filming, but due to erosion, one was removed, leaving 38 facades.
Step-by-step explanation:
After filming The Lord of the Rings, 39 hobbit hole facades were initially left intact. Over time, they turned into a tourist attraction known as the Hobbiton Movie Set. However, this attraction does not quite match any of the given options (a) 10 b) 20 c) 30 d) 40), since one hobbit hole was removed due to erosion. Thus, the tourist destination currently features 38 Hobbit hole facades, which is closest to option c) 30 when rounding to the nearest ten.