The correct answer is 'in.' Key Points - Let us look at the usage of the given options: - We use at to talk about points in time, ages and some periods of time. - Example: I was up at 6 am this morning. - We can use 'with' when you're talking about people, or things being together. - Example: I was with Jane yesterday when the accident happened. - We use by meaning 'not later than' to refer to arrangements and deadlines. - Example: The postman is always here by 11 am. - We use in for something inside or enclosed by something else. - Example: I was travelling in her car. - We use inside when we refer to the inner part of something. - Example: He is inside that house. - Correct sentence: We travelled in Mr. Barthwal's car.