The correct answer is option C, that is, 30 minutes.
It is essential to get a good night sleep for good mental, physical, and emotional health. It is as essential as consuming a healthy diet and doing enough exercise. It has been found that about half of the adults do not shut their eyes, with many admitting that they lie awake at night fretting about their worries.
Thus, to tackle the situation, one should be preparing to go to sleep before 30 minutes of light out. One needs to put the body and brain in the right state where sleep can take place easily.