"i've got it! " john exclaims when he finally cracks a brain-teaser problem he's been working on. john is experiencing:

In the given scenario, John is experiencing insight. An insight is where an individual was able to have a sort of understanding that could be either be accurate or deep. It could be seen in the scenario above as John demonstrates his way of solving or understanding the problem in means of saying that he has got the answer.

a. the moon was locked into orbit by the earths gravity as it was passing by and capture hypothesis i think