The correct answer is A. Ward Leonard control.
A Ward Leonard control system is an open-loop control system. This means that the system does not have any feedback mechanism to control the output. The input to the system is the desired output, and the output is the actual output. The system will try to produce the desired output, but it will not be able to correct for any errors that occur.
A field controlled D.C. motor is a closed-loop control system. This means that the system has a feedback mechanism to control the output. The input to the system is the desired output, and the output is the actual output. The system will try to produce the desired output, and it will correct for any errors that occur.
A stroboscope is a device that produces a series of flashes of light at a regular interval. The frequency of the flashes can be adjusted to match the frequency of rotation of an object. This allows the object to be viewed in slow motion.
A metadyne is a type of generator that is used to produce high-voltage, low-current electricity. It is used in a variety of applications, including welding, X-ray machines, and particle accelerators.
In conclusion, the correct answer is A. Ward Leonard control.