Which of the following is the BEST definition of a buyer persona?

Which of the following is the BEST definition of a buyer persona?
  A)  Personas are your target markets and represent your ideal customers.
  B)  Personas are semi-fictional characters that represent your ideal customers.
  C)  Personas are characters you create based on job title that represent who you’re trying to reach.
  D)  Personas are profiles you create based on one or two of your best customers.