MCT for flights originating in Hong Kong

I have a two-leg flight from Hong Kong to Germany with a very short 80-minute layover in Beijing. Which MCT (Minimum Connection Time) applies to this flight? Is it

(a) 120 minutes, i.e. a domestic-to-international connection, or

(b) 60 minutes, i.e. an international-to-international connection (as Hong Kong flights are usually treated the same as international flights in capital city)?

Thanks for your help!