At the annual stockholders meeting, investors heard a presentation on the numerous challenges facing the company, including among them the threat from a rival's multibillion-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 multibillion-dollar patent-infringement suit and the declining sales for

B. which includes the threat of a rival's multibillion-dollar patent-infringement suit and declining sales of

C. included among these the treat from a rival's multibillon-dollar patent-infringement suit as well as a decline in sales for

D. among them the threat of a rival's multibillion-dollar patent-infringement suit and the decline in sales of

E. among these the threat from a rival's multibillion-dollar patent-infringement suit as well as the decline in sales for

What's the rule for using among them and among these?