What can be used to prevent the mixing of hot and cold air to improve the cooling efficiency of cClass enclosures installed in the 10000 Series cabinet? (Select two.)

A.
HP Rack Coupling Kit

B.
HP 1U Universal Filler Panel

C.
HP 10000 Series Rack Airflow Optimization Kit

D.
HP 10000 G2 Series Front Doors

Explanation:
http://h18000.www1.hp.com/products/quickspecs/12810_div/12810_div.html