please answer me the questions, thanks much.

Question 20 4 pts According to economists, the goal of a consumer is to spend available income so as to maximize utility. O True O False Question 19 4 pts If the Marginal Utility to Carol of sleeping for an extra hour (from 6:00 am to 7:00 am) is negative, then (O Carol is better off getting up at 6:00 am. (O Carol is better off getting up at 7:00 am. (O Carol's Total Utility of sleeping must be negative. (O Carol's average utility from every hour he sleeps must be negative. O Carol is suffering from a sleep disorder. Question 18 4 pts When Dave receives a pay increase, his income increases. Dave has a budget constraint model that gives him the choice of pizzas or tacos for lunch. With his pay raise, Dave's budget increases from ten dollars to twenty dollars a week for pizzas and tacos. Therefore, Dave's budget constraint has O shifted inward to the left with a decrease in income. (O shifted outward to the right for both pizzas and tacos. (O shifted inward to the left for pizzas only. O shifted inward to the left for tacos only (O experienced no change in preferences or consumption