Here, the problem is violation of parallelism in C
..much of the...was expended on the creation of.. as well as constructing and decoration of.
B maintains this parallelism well.
As for the distinction between and / as well as
Consider the following examples -
1) The mayor as well as his brothers is going to prison.
2) The mayor and his brothers are going to jail.
Phrases such as together with, as well as and along with are not the same as and. The phrase introduced by as well as or along with will modify the earlier word (mayor in this case), but it does not compound the subjects (as the word and would do).
scio me nihil scire