A company uses Routers R1 and R2 to connect to ISP1 and ISP2, respectively, with Routers I1 and I2 used at th e ISPs. R1 peers with I1 and R2; R2 peers with I2 and R1. R1 and R2 do not share a common subnet, relying on other routers internal to the Enterprise for IP connectivity between the two routers. Which of the following could be used to prevent potential routing loops in this design?（）

• A、Using an iBGP mesh inside the Enterprise core
• B、Configuring default routes in the Enterprise pointing to both R1 and R2
• C、Redistributing BGP routes into the Enterprise IGP
• D、Tunneling the packets for the i BGP connection between R1 and R2