Trekking in Upper north-eastern Himalayas is dangerous for reasons ranging from tough terrain to the absence of regulations to protect visitors and a serious lack of information about various routes.
A. to the absence of regulations to protect visitors and a serious lack of information about various routes
Correct --> Ranging from X to Y is the correct idiomatic expression as well as elements of Y i.e the absence of...and a serious lack of... are parallel B. to the absence of regulations to protect visitors and seriously lacking information about various routes
Incorrect --> Ranging from X to Y is correctly used, but elements of Y ie the absence...and seriously lacking ... are not parallel to each other.C. and the absence of regulations to protect visitors and a serious lack of information about various routes
Incorrect --> incorrect idiomD. and the absence of regulations to protect visitors to a serious lack of information about various routes
Incorrect --> incorrect idiom
E. to the absence of regulations to protect visitors and to the serious lack of information about various routes
Incorrect --> Ranging from X to Y is correctly used, but elements of Y ie the absence...and to the serious lack ... are not parallel to each otherWould like some KUDOS if you liked my explanation