What is the reason for this failure?

An administrator is creating interface objects to better segment their network but is having trouble adding interfaces to the objects .

What is the reason for this failure?
A . The interfaces are being used for NAT for multiple networks.
B . The administrator is adding interfaces of multiple types.
C . The administrator is adding an interface that is in multiple zones.
D . The interfaces belong to multiple interface groups.

Answer: B

Explanation:

https://www.cisco.com/c/en/us/td/docs/security/firepower/620/configuration/guide/fpmc-config-guide-v62/reusable_objects.html#ID-2243-000009b4

"All interfaces in an interface object must be of the same type: all inline, passive, switched, routed, or ASA FirePOWER. After you create an interface object, you cannot change the type of interfaces it contains."