When BGP tuning is used， how is packet flow into the e-commerce module controlled？（）

• A、by tracking the status of objects along the path to the e-commerce module
• B、by detecting undesirable conditions along the path to the e-commerce module
• C、by using the MED to communicate the site preferences for traffic to multiple ISPs
• D、by communicating the available prefixes， routing policies， and preferences of each site to its ISP
• E、by moving the SLB to a position where selected traffic to and from the servers does not go through the SLB