In Which of the Following Situations May the Taxpayer Take

In which of the following situations may the taxpayer take an education expense on Schedule C?

A) John, a plumber by trade, is taking classes to qualify as an electrician so he may take on more complex contrator jobs.
B) Henry, an administrative assistant, is taking an advanced Word computer program class through an adult school program.
C) Barbie is flying on numerous commercial airplanes in order to observe the flight attendants so that she may improve her public relations skills.
D) Ann Marie is taking a review course in order to pass the certified financial planner examination.