。
She asked the police officer for directions.
Literal
She [topic-は] police-officer [to-に] road/way [object-を] asked.
Two cooperating particles: に marks the addressee (the person being asked) while を marks what is asked about. 道を尋ねる ('to ask the way') is the standard collocation for asking directions — the noun 道 covers physical roads and figurative paths alike. 尋ねる is somewhat more formal than 聞く: it specifically denotes a directed inquiry rather than the all-purpose 'hear/ask' of 聞く, and it's the verb you'd see on a written sign or in news writing.