(a) Controller, Maria Burroughs, in a recent speech said, “I rarely see a real variable cost or a truly fixed cost.” What did she mean?

(b) She also commented, “Some of my friends define semivariable costs, semifixed costs, step costs, and mixed costs differently. Other friends often use these terms interchangeably. And | like all of my friends.” Was she just trying to be funny, or is there truth in her quip? Explain.