Sentence Correction

Accentuated by the cold weather during rainy season, moisture and dampness in soil lead to decomposition of organic matter into humus enabling mushrooms to flourish.
A. enabling mushrooms to flourish.
B. for the mushrooms to flourish.
C. for flourishing mushrooms.
D. that enable the mushrooms to flourish.(for correct option, it should be enables)
E. that the mushrooms can flourish

The sentence can be restructures as follows....
.....moisture and dampness in soil decomposes organic matter into humus that enables the mushrooms to flourish..

Or for the mushrooms to flourish....

But not option A..as it refers to the ongoing action with the action of the main verb. But the action of the participle will happen sometime after the action of the main verb, decompose. Or the action of the participle coexists with the action of the main verb, decompose.?

Accentuated by the cold weather during rainy season, moisture and dampness in soil lead to decomposition of organic matter into humus enabling mushrooms to flourish.

A. enabling mushrooms to flourish.
B. for the mushrooms to flourish.
C. for flourishing mushrooms.
D. that enable the mushrooms to flourish.(for correct option, it should be enables)
E. that the mushrooms can flourish

Removes/delete the unnecessary phrases/clauses inserted in sentence to make it difficult and then read this sentence as:

Accentuated.., WITH moisture and dampness in soil lead to decomposition...into humus for the mushrooms to flourish.
I inserted BOLD LETTERED "WITH" to simplify and to delete other phrases inserted to confuse.
GMAT loves simple concise english. And "that enables the mushrooms to flourish" is too wordy So I think that "B" is right choice.
As far as your question whether or not they Co-Exist, Yes! they coexist. Decomposition into humos is happening on side and mushrooms are flourishing on the other side, simultaneouly.