Answer:
Now, it is called a building because the 'ing' in the English language is added to certain verbs to make them nouns. The verb 'built' is suffixed with 'ing' to make the thing a noun- Building.
Explanation:
We speak English ♀️♀️♀️♀️♀️♀️♀️♀️
Let him have a day off and find a replacement
A... Common sense but its fine, A is the answer you are looking for dude.