How many of the following statements are true? I. Given just &, a student is more likely to be lazy than hard working; II. X is irrelevant to Y given &; III. A hard-working student in a difficult...

How many of the following statements are true?

I. Given just &, a student is more likely to be lazy than hard working;

II. X is irrelevant to Y given &

III. A hard-working student in a difficult class is more likely to get an A than a lazy student in an easy class;

IV. X is relevant to Y given Z and &.

a. 0 or 4

b. 1

c. 2

d. 3