Donna has a new job. her annual starting salary is $17,600, and she receives a raise of $850 at the end of each year. which expression models her salary at the beginning of her nth year? what will donna's salary be at the beginning of her 5th year?

a. 17600 + 850(n - 1); $21,000
b. 17600 + 850(n + 1); $22,700
c. 17600 - 850(n - 1); $24,200
d. 17600 + 850n; $21,850