When Is Martha More Likely to Hire a Plumber to Repair

When is Martha more likely to hire a plumber to repair a leaky drainpipe?  

A)  when the tax rate on Martha's earned income rises 
B)  if Martha already owns the specialized tools required to complete the plumbing repair work 
C)  following an increase in the opportunity cost of Martha's time 
D)  when Martha obtains more knowledge and experience in plumbing repair work