max bought some e-books for $8.99 each and some magazines at $3.99 each. if E represents number of e-books and M represents number of magazines, which equation describes the relationship between these two variables if he spent a total of $68.89 on these items?
A- 8.99e-3.99m=68.89
B- 3.99e+8.99m=68.89
C- 3.99e-8.99m=68.89
D- 8.99+3.99=68.89