Solve. Use Interval Notation to Express the Range

Multiple Choice

Solve. Use interval notation to express the range.
-On the first four exams, your grades are 79, 82, 75, and 80. There is still a final exam, and it counts as two grades. You are hoping to earn a C in the course. This will occur if the average of your six exam grades is greater than or equal to 70 and less than 80. What range of grades on the final exam will result in earning a C?

A) [52, 82)
B) [52, 82]
C) [34, 84]
D) [34, 84)