If the binary operation * is defind on the set Q+ of all positive rational numbers by a * b = \(\frac{a b}{4}\). Then, \(3 *\left(\frac{1}{5} * \frac{1}{2}\right)\) is equal to

(a) \(\frac{3}{160}\)

(b) \(\frac{5}{160}\)

(c) \(\frac{3}{10}\)

(d) \(\frac{3}{40}\)