2. Which of the following do you think reflect sound economic thinking? Explain your answer.

(a) "I paid $200 for this economics course. Therefore, I'm going to attend the lectures even if they are useless and boring."

(b) "Since we own rather than rent, housing doesn't cost us anything."

(c) "I own 100 shares of stock that I can't afford to sell until the price goes up enough for me to at least get back my original investment."

(d) "It costs to produce private education, whereas public schooling is free."