Which of the following is an example of Simpson's paradox?

	a.	A new Government health care plan decreases the average medial expenses for all households except those earning $50,000 or less whose expenses increased
	b.	A new early childhood curriculum shows learns that children on average can read more words than the prior curriculum with the exception of children with documented special needs who learn less words than before.
	c.	A new diet plan claims an average weight loss of 5 lbs over 5 weeks except for men over 40 who gain weight on average
	d.	All of these are examples