Final answer:
The correct preposition to complete the sentence is 'dans' which means 'in' in English.
Step-by-step explanation:
The correct preposition to complete the sentence is dans. The sentence can be translated to 'The car is in the garage.' In French, the preposition 'dans' is used to indicate location inside a place, such as 'dans le garage' meaning 'in the garage'.
Learn more about French prepositions