The answer C correctly uses possessive form and is the right answer. It's not A because there is only one George so the apostrophe is in the wrong place. In B, there's not even an apostrophe and it's not clear as to whether there is only one cousin or two or more cousins. In answer D, here should not be an apostrophe for develops.
The only noun I know derived from the verb to entomb would be the noun entombment.
It is an abstract noun, which means that it doesn't have a physical shape - you cannot touch it or smell it, just like with love, or hate, or happiness. Entombment is the process of placing a dead body into a tomb, or a grave.
One place is probably more home which is is new york home. But depending how long he has stayed on the island his home as probably developed into the home on the island. It really depends.
Answer
while is the answer to the question
The first one Running barefoot is clearly the best and most natural way to run