Could you please help to solve this question? Thank you very much!

3. True or false? Please explain why. a. If the production function has strictly convex isoquants and is differentiable, then there will always be an interior solution to the cost-minimization problem: production will use both inputs. Assume that there are linear isocost curves. b. Alan runs a restaurant in Central. The city just lowered the annual fee to renew Alan's liquor license. This fee reduction will change the number of meals Alan has to serve to minimize his variable cost in the short run. c. Unlike indifference curves, isoquants may intersect. d. A firm may operate on the downward-sloping portion of its short-run ATC curve in the short run. e. You have finished all but one semester of college, and you are thinking of dropping out before you finish your degree, to start a company. The time you've already put into the degree is a sunk cost. f. You bought a non-refundable, non-transferable airplane ticket from HK to LA for an upcoming trip. You are deciding whether to fly on those dates, or not. Given that tickets are not refundable, the airline only allows you to cancel entirely or move the dates of your trip (with a change fee and any fare difference): this policy means the amount you paid for your original ticket is a sunk cost