In ancient Thailand, much of the local artisans' creative energy was expended for the creation of Buddha images and when they constructed and decorated the temples that enshrined them.
(A) much of the local artisans' creative energy was expended
for the creation of Buddha images and when they constructed and decorated the temples that enshrined them
'expended for' is unidiomatic. The more glaring issue, however is, 'FOR the creation...' and 'WHEN they constructed...' are NOT parallel
(B) much of the local artisans' creative energy was expended on the creation of Buddha images and on construction and decoration of the temples in which they were enshrined
CORRECT(C) much of the local artisans' creative energy was expended on the creation of Buddha images
as well as constructing and decoration of the temples in which they were enshrined
I suppose we can let 'as well as' slip...'and' would be preferred. But again the issue is 'constructing and decoration' are not parallel with 'the creation of a Buddha images' (a noun)
(D) creating images of Buddha accounted for much of the local artisans' creative energy, and also constructing and decorating the temples enshrining them
Just a mess..
(E) the creating of Buddha images accounted for much of the local artisans' creative energy as well as construction and decoration of the temples that enshrined them
Another mess...