Multi-choice problem: Continue writing the next sentence in this paragraph:

How to maintain your car engine for higher efficiency
Check the engine's cooling system.
The cooling system in an engine helps it to maintain its internal temperatures and transfer excessive heat out of the engine. The cooling system must not be left unattended every time when you plan a long journey.

Choose your answer from: 1. Check the windows for condensation. If condensation is spotted on the interior of the windows in the car, immediately close the windows. 2. A light bulb should read the temperature as ambient temperature. Find or purchase an air compressor to store exhaust gas. 3. If you have a car that cannot keep reliance on the cooling system, this includes installing all the maintenance necessary for your engine, maintenance, transport and servicing until you reach the end of your trip. This can involve the installation of an installation and maintenance manual. 4. The cooling system contains different parts, such as the radiator, thermostat, water pump and coolant. A straightforward way to look after and safeguard your engine from overheating is by checking that it has the appropriate quantity of coolant flowing inside the engine's cooling chambers.
4.