Based on the show ip route isis output on R1, which statement is true? （）

• A、The i su 10.1.0.0/23 route is a suppressed route.
• B、The i su 10.1. 0.0/23 route is a summary route.
• C、The i su 10.1.0.0/23 route is an IS - IS external route.
• D、The R1 IS - IS router is an ASBR.
• E、The R1 IS - IS router is an ABR that belongs to multiple IS - IS areas.
• F、The R1 IS - IS router is performing route aggregation  and is suppressing the more specific 10.1.0.0/23 prefix.