The First Pepsi Yields Craig 18 Units of Utility and the Second

The first Pepsi yields Craig 18 units of utility and the second Pepsi yields him an additional 12 units of utility.His total utility from three Pepsis is 38 units of utility.The marginal utility of the third Pepsi:

A) is 26 units of utility
B) is 6 units of utility
C) is 8 units of utility
D) is 4 units of utility
E) is 2 units of utility