A number m is randomly selected from the set \{11,13,15,17,19\}, and a number n is randomly selected from \{1999,2000,2001, \ldots, 2018\}. What is the probability that m^{n} has a units digit of 1 ?
Answer Choices
A. \dfrac{1}{5}
B. \dfrac{1}{4}
C. \dfrac{3}{10}
D. \dfrac{7}{20}
E. \dfrac{2}{5}