I am trying to understand the C3 Linearization Algorithm (Python) and I understood most part of it, but I just wonder why we should pick the first “valid candidate” incase there are more than one “valid candidates”

I am trying to understand the C3 Linearization Algorithm (Python) and I understood most part of it, but I just wonder why we should pick the first “valid candidate” incase there are more than one “valid candidates”