Like so many hints in this section…the way to find root is by looking for a file that’s normally not there. Think about what kind of file has the power (permission) to alter things that normally are restricted/protected? For the people who didn’t find it in the enumeration scripts…look closer.
Also for the ones that are asking help with “I found file x******z and don’t know what to do with it”…it’s a dead give-away. With the right find command you still give the answer, which can count as a spoiler.