Answer: c) CCFL back-light is failing
Explanation: CCFL (cold cathode fluorescent lamps) back-light is the light technology that is used in the displays of the devices like LCD TV, LCD monitor etc. This technology was used earlier in the display device units
According to the question's case ,LCD monitor flickering or fluctuation can occur due to the disturbance or damage in the CCFL back-light resulting in the failure.
Other options are incorrect because refreshing option is not concerned with the display light .LED light is not used the mentioned monitor.Thus, the correct option is option(c).
