Answer: The Printing press, airplane, automobile
Explanation:
The Modern Age is considered the age of science and technology because at this age there are many inventions that people are using now and that made our life easier.
Examples of science and technology inventions: The Printing press, Light bulb, Airplane, Computer, Vaccines, Telephone, Automobile, Camera, Refrigeration, Clock, and more.
There are also Vaccum, the Radar, Automatic washing machine, Email, Internet, Mobile phone.
The answer is A. They were serving for pay and were willing to switch sides.