A baker used 40% of a 50kg bag of flour. If \(\frac{1}{8}\) of the amount used was for the cake, how many kilogram of flour was used for the cake?

• A.2\(\frac{1}{2}\)
• B.6\(\frac{1}{2}\)
• C.15\(\frac{3}{8}\)
• D.17\(\frac{1}{2}\)