At the annualstock holders meeting, investors heard a presentation on the numerous challenges facing the company, including among them the threat from a rival's multi-billion dollar patent-infringement suit and the declining sales for the company's powerful microprocessor chip.

A. including among them the threat from a rival's multi-billion dollar patent-infringement suit and the declining sales for
B. which includes the threat of a rival's multi-billion dollar patent-infringement suit and declining sales of
C. included among these the threat from a rival's multi-billion dollar patent-infringement suit as well as a decline in sales for
D. among them the threat of a rival's multi-billion dollar patent-infringement suit and the decline in sales of
E. among these the threat from a rival's multi-billion dollar patent-infringement suit as well as the decline in sales for

OA is D .

My question : I could clearly get down to A and D . However, i chose A over D because i thought modifier "among them the threat of a rival's multi-billion dollar patent-infringement suit and the decline in sales of " this way is incorrect. So is not the case as is apparent from the right modifier.

Could an expert help to explain what type of modifier it is, so i could use the same in other construct.