Factoring by Grouping

Janet wants to calculate the average of her Algebra exam grades. Unfortunately, Janet's teacher never returned the exams (she is a tough teacher!) and Janet doesn't know her grades. Her teacher did give her a hint though! She told Janet that the product of her three grades is given by the polynomial $x^3 + 40x^2 +525x + 2250$, where $x$ is the class average for all of the exams. Janet learns that the class average is 70. Which of the following could be Janet's grades for her three exams?