I prefer the first candidate because he has worked in tourism industry for 20 years and he has many experiences..also seems hard - working and he wants more contact with people...
the second candidate she worked as a tour guide and she finished tourism course but she doesn't more experiences..
the last candidate he has studied history and speak very good english..moreover he has worked as tour operator but he has a disadvantage is informal and he has low level of written english..
finally i believe that the candidate A is a best choice..!!