If friction is acting along the plane upwards
then in this case we will have
For equilibrium of 100 kg box on inclined plane we have

also for other side of hanging mass we have

now we have




In other case we can assume that friction will act along the plane downwards
so now in that case we will have

also we have

now we have





<em>So the range of angle will be 23.45 degree to 37 degree</em>
I believe that is true. Anaerobic means without (much) Oxygen. This usually builds up lactic acid in muscles.
I would go with C because all the rest of the answer are sitting on something.
The question is fishing for the answer "<em>radiation</em>", but it never manages to make itself completely unambiguous.
It doesn't make it clear that there is no material in the "subject space". It just tries hard to imply that with the example of sunshine.
If there's any material stuff on the way from the "source" to the "subject space", then <u><em>conduction</em></u> could also be an acceptable answer.