Which feature that applies to HP Z1 workstations simplifies upgrades and serviceability?

A.
Rack-mount tower with integrated handles

B.
Small form factor high efficiency chassis

C.
All-in-one tool-less access case

D.
Compact tower form factor for maximum expandability

Explanation:
http://h20331.www2.hp.com/Hpsub/downloads/Z1_Chassis_System_Highlights083012.pdf (page
2)