Can you please walk me through the steps on how to reach one of these answers? I am having trouble making sense of this problem

4. The following series converges by the alternating series test. Which one of the following inequalities, when solved, determines the smallest number of terms required to approximate the value of the series E(-1)* tan 7T k + 1.1 k=1 by the nth partial sum Sn with an error [ Rn) n + 2.1 1 (c ) tan (10-10) n + 0.1 (d) tan (10-10)