disconnect a multiparty call when the call initiator hangs up?

Which Cisco Unified Communications Manager service parameter should be enabled to

disconnect a multiparty call when the call initiator hangs up?
A . Block OffNet to OffNet Transfer
B . Drop Ad Hoc Conference
D . 225 Block Setup destination
E . Enterprise Feature Access code for conference

Answer: B

Explanation:

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/10_0_1/ccmsys/CUCM_BK_SE5FCFB6_00_cucm-system-guide-100/CUCM_BK_SE5FCFB6_00_cucm-system-guide-100_chapter_011000.html#CUCM_TK_DFC66444_00