Question on Schweser Topic 3.7 page 301

I was just doing the concept checkers and one question seems too hard for my brain to accomplish. How come that in question 3 you can’t make a profit when B or C applies. Maybe I don’t get the question but when I buy a long future in contango and then the future prices increases how come I don’t make a profit? P.S. Any chance under B and C it is possible to make a profit but not necessary? Also how come when the future prices increases I can’t just sell the future for a profit?