9. Why is it generally better to sell rather than exercise an American option?

a.	an American option can only be exercised at its expiration
	b.	selling is more valuable
	c.	you get the time premium if you sell the option, but not if you exercise it
	d.	because the time premium is virtually always positive
	e.	A and B
	f.	A and C
	g.	A and D
	h.	B and C
	i.	B and D
	j.	C and D
	k.	all but A
	l.	all but B
	m.	all but C
	n.	all but D
	o.	all are true