The correct configuration for PE1 to connect AS 200 of the service provider with AS 100 of enterprise ABC using BGP, considering the VRF RT 100:10 is already configured, would involve setting up BGP with the correct neighbor and route distinguisher settings. Option C is likely the correct choice as it specifies the BGP neighbor to be within the enterprise ABC’s AS 100 and includes the address family configuration necessary for VRF-aware BGP sessions. References := The Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials provide detailed instructions on configuring BGP in a service provider environment, including the use of VRFs and route distinguishers. For more information, please refer to the official Cisco documentation and course materials related to SPCOR1.