James takes 75 minutes to complete a writing assignment, and 15 minutes to complete a science assignment. James is required to spend more than 300 minutes on his assignments. According to his schedule, he can complete at most 20 assignments this week.

Which system of inequalities can be used to determine the number of writing assignments (w) and the number of science assignments (s) James can complete this week?
A. 75w+15s>300
w+s≤20
B. 15w+75s<300
w+x≤20
C. 75w+15s≥300
w+s≥20
D.
15w+75s>300
w+s≤20