Which of these sentences uses quotation marks and other punctuation correctly?

 

	a.	Whenever we were rude to other kids, our mom would remind us that "what goes around, comes around;" I didn't understand it as a child, but now I know how true it is.
	b.	Whenever we were rude to other kids, our mom would remind us that "what goes around, comes around" I didn't understand it as a child, but now I know how true it is.
	c.	Whenever we were rude to other kids, our mom would remind us that "what goes around, comes around"; I didn't understand it as a child, but now I know how true it is.
	d.	Whenever we were rude to other kids, our mom would remind us that "What goes around, comes around," I didn't understand it as a child but now I know how true it is.