A group of 59 traders sell Gari, Rice or Maize. 26 of them sell Gari, 42 sell maize and 8 sell only rice. 15 sell maize only, 10 sell both Gari and rice. 16 sell rice and maize and each trader sells at least one of the food items. Find the number of traders who sell. a) Gari or maize b) Gari and maize c) only two of the items