Refer to the exhibit.An engineer must design a WAN solution so that ISP-1 is always preferred over ISP-2. The path via ISP-2 is considered as a backup and must ...

Refer to the exhibit.An engineer must design a WAN solution so that ISP-1 is always preferred over ISP-2. The path via ISP-2 is considered as a backup and must be used only when the path to ISP-1 is down. Which solution must the engineer choose?

A. R1: - Routes advertised to ISP-1: 0x AS-path prepend - Routes received from ISP-1: HIGH local-preference - Routes advertised to R2: no action - Routes received from R2: community NO-EXPORT R2: - Routes advertised to ISP-2:5x AS-path prepend - Routes received from ISP-2: LOW local-preference - Routes advertised to R1: community NO-ADVERTISE - Routes received from R1: no action B. R1: - Routes advertised to ISP-1: 0x AS-path prepend - Routes received from ISP-1: HIGH local-preference - Routes advertised to R2: community NO-EXPORT - Routes received from R2: no action R2: - Routes advertised to ISP-2: 5x AS-path prepend - Routes received from ISP-2: LOW local-preference - Routes advertised to R1: no action - Routes received from R1: no action C. R1: - Routes advertised to ISP-1: 0x AS-path prepend - Routes received from ISP-1: LOW local-preference - Routes advertised to R2: community NO-ADVERTISE - Routes received from R2: no action R2: - Routes advertised to ISP-2: 5x AS-path prepend - Routes received from ISP-2: HIGH local-preference - Routes advertised to R1: no action - Routes received from R1: community NO-ADVERTISE D. R1: - Routes advertised to ISP-1: 5x AS-path prepend - Routes received from ISP-1: LOW local-preference - Routes advertised to R2: community NO-ADVERTISE - Routes received from R2: no action R2: - Routes advertised to ISP-2: 0x AS-path prepend - Routes received from ISP-2: HIGH local-preference - Routes advertised to R1: community NO-EXPORT - Routes received from R1: no action