Sam wants to improve his GPA. to earn a 4.0 this semester. His prior GPA was a 2.75. Imagine that there is an equation that says his new GPA could be calculated based on the number of hours he spends studying, his class attendance, and his prior GPA. Written as an equation, it is Grade (0.50 x hours spent studying) +(0.25 x class attendance hours) + (0.25 x prior GPA). Sam plans to attend class for 4 out of 4 hours each week. Use the equation to determine approximately how many hours per week Sam needs to study to earn a 4.0. Select one: a. 2.3 hours b. 4.0 hours c. 1.7 hours d. 4.6 hours