Which of the following sentences is punctuated correctly?
a.
sam saw that the fence was full of splinters (some of which were very large) and did not want to climb over.
b.
sam saw, that the fence was full of splinters some of which were very large, and did not want to climb over.
c.
sam saw that the fence was full of splinters—some of which were very large, and did not want to climb over.
d.
sam saw that the fence (was full of splinters some of which were very large) and did not want to climb over.