Given that \(ab<0\) and \(a>b,\) which of the following must be true?

I. \(a>0\)

II. \(b>0\)

III. \(\dfrac1{a}>\dfrac1{b}\)

A. I only
B. II Only
C. I and III Only
D. II and III Only
E. I, II and III

Answer: C

Source: Manhattan GMAT