Critical Reasoning

The chanterelle, a type of wild mushroom, grows beneath host trees such as the Douglas fir, which provide it with necessary sugars. The underground filaments of chanterelles, which extract the sugars, in turn provide nutrients and water for their hosts. Because of this mutually beneficial relationship, harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree.
Which of the following, if true, casts the most doubt on the conclusion drawn above?
(A) The number of wild mushrooms harvested has increased in recent years.
(B) Chanterelles grow not only beneath Douglas firs but also beneath other host trees.
(C) Many types of wild mushrooms are found only in forests and cannot easily be grown elsewhere.
(D) The harvesting of wild mushrooms stimulates future growth of those mushrooms.
(E) Young Douglas fir seedlings die without the nutrients and water provided by chanterelle filaments.

Is the conclusion OK in this argument? I know that English is not my native language, but I think that the sentence is logically incorrect: "Because of this mutually beneficial relationship, harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree". It seems to me that "despite of" will be good. Can someone pls help? And also what do you think what is the OA?

The conclusion is phrased correctly and "despite" would not be a good alternative to "because of."
The conclusion states that:
1. the relationship is BENEFICIAL
SO
2. harvesting the chanterelles endangers thie host (the tree).

A - out of scope, we are not interested in all wild mushrooms
B - this statement does not weaken the conclusion, it only introduces new information
C - out of scope, similarly to answer A, this statement neither weakens nor strengthens the argument
D - correct, it suggests that harvesting the chanterelles can be beneficial for them because they will grow more rapidly in the future
E - incorrect, this answer strengthens the conclusion

Conclusion : Harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree.
[spoiler]IMO D
Since harvesting will stimulates future growth , Douglas fir won't be endangered [/spoiler].

I don't understand one: if it is beneficial, why it must endanger the tree? that is why I ask why "because"?

It is beneficial and hence harvesting it will endanger

I am confused b/w D and E.The argument goes as mentioned below

Chanterelles,provide nutrients and water -> Harvest Them -> Endanger the Douglas fir

It shows a cause and effect.

Cause s Chanterelles,provide nutrients and water
Effect s Do not harvest Chanterelles as it benefits the Douglas fir

So an alternate cause will weaken the conclusion -
D - It does not weaken.If they harvest Chanterelles it grow more and will be much better for the Douglas fir.
E - Provide a New Mutual Relationship or Reason for not harvesting Chanterelles.

Please correct if the above explanation is wrong.