Find only the rational zeros of the following function. If there are none, state this.
f(x) = x^4 + x^3 - 15x^2 - 13x + 26
Select the correct choice below and, if necessary, fill in the answer box within your choice.
A. The rational zero(s) is/are
(Use a comma to separate answers as needed.)
B. There are no rational zeros.