Which action must be taken before a custom quarantine that is being used can be deleted? 

Answer options:

A. Delete the quarantine that is assigned to a filter.
B. Delete the quarantine that is not assigned to a filter.
C. Delete only the unused quarantine.
D. Remove the quarantine from the message action of a filter.

D

Reference: https://www.cisco.com/c/en/us/td/docs/security/esa/esa12-0/user_guide/b_ESA_Admin_Guide_12_0/ b_ESA_Admin_Guide_12_0_chapter_011111.html