While troubleshooting an EIGRP routing problem you notice that one of the routers have generated a large number of SIA messages. What are two possible causes for EIGRP Stuck - In -Active routes?（）

• A、Some quer y or reply packets are lost between the routers.
• B、The neighboring router starts receiving route updates from this router.
• C、A failure causes traffic on a link between two neighboring routers to flow in only one direction(unidirectional link).
• D、Th e neighboring router stops receiving ACK packets from this router.