The inference about the Highwayman that is best supported by the entire poem is that he is a thief who steals from people on the highway.
Step-by-step explanation:
The inference about the Highwayman that is best supported by the entire poem is option B: He is a thief who steals from people on the highway.
The poem consistently portrays the Highwayman as a notorious and daring character who robs travelers on the highway. This is evident through lines such as 'He'd a French cocked-hat on his forehead, a bunch of lace at his chin,' and 'With the white road smoking behind him and his rapier brandished high.' These details paint a clear picture of a criminal figure who conducts his illicit activities on the road.