What does a blinking amber LED usually indicate on a SATA hot plug drive?

A.
The drive has failed.

B.
The drive has a predictive failure.

C.
The drive is active and busy.

D.
The drive is active and offline.

Explanation:
http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c01693939/c0169393
9.pdf(page 7)