The correct answer to this question is B, In parallel. A battery can be connected in two ways. Those ways are parallel and series. A parallel connection is when the capacity is doubled. Though doubled, the voltage of one of the batteries is still maintained.
This type of connection is used in devices like laptops. Scooters also use parallel connections. The second connection is a series. In this connection, the voltage is also doubled, but the difference between the two is that when doubled, the capacity rating is maintained. This type of connection can also be used in scooters, as well as vehicles for kids like small cars.