As an experienced technician, you are responsible for Technical Support. Which of the following descriptions is correct about the characteristic of SLB one arm mode?（）

• A、This out-of-band approach supports scaling
• B、SLB is not inline.
• C、Mode is not as common as bridge or routed mode.
• D、Return traffic requires PBR, server default gateway pointing to SLB, or client source NAT.