The suggested answer is C.
In some networks, traffic is configured to take alternate paths for inbound and outbound traffic. This routing is called asymmetric routing.
However, if you want to combine flows from multiple QRadar QFlow Collector components, you must configure flow sources in the Asymmetric Flow Source
Interface(s) parameter in the QRadar QFlow Collector configuration.
The Yes option enables the QRadar QFlow Collector to recombine asymmetric flows.
The No option prevents the QRadar QFlow Collector from recombining asymmetric flows.
References:
http://www.ibm.com/support/knowledgecenter/SS42VS_7.2.7/com.ibm.qradar.doc/t_qradar_adm_config_qflow_col.html