Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Nuclear fusion occurs more rapidly in hydrogen bomb explosion, and occur continually in the Sun, releasing energy essential for the life on the earth.
Reason R: Nuclear reaction of less massive nuclei coming together to form less stable and more massive nuclei is referred as nuclear fusion.
In the light of the above statements, choose the correct answer from the options given below: