If -1 < a < 0 < b < 1, which of the following must be less than 0?
I.	a/b
II.	b/a
III.	ab
Choose the correct choice
A) I only
B) II only
C) III only
D) I,II and III
E) None of the above
We could solve this easily using examples.   I is true since a&lt;0, b&gt;0 therefore a/b&lt;0   II is true since a&lt;0, b&gt;0 therefore b/a&lt;0   III is true since a&lt;0, b&gt;0 therefore ab&lt;0   So, the answer is I,II and III
<result>D</result>
If -1 < a < 0 < b < 1, which of the following must be less than 0?
I.	a/b
II.	b/a
III.	ab