D Question 15 4 pts Alexandra has determined that studying an hour for her economics quiz will improve her grade on the quiz from 75 to 100. She also determines that this improvement is worth $20. To study for an hour for her economics quiz, however, she will have to work one fewer hour at her part-time job. Alexandra should: O study for the quiz as long as her hourly wage rate is less than $20. O study for the quiz as long as her hourly wage rate is more than $20. O study for the quiz only if her hourly wage rate is exactly $20. not study for the quiz because earning a higher grade cannot have a dollar value