Answer
graph $(b)$
Work Step by Step
1) Either graph sample points for the function at certain values ($n=1,2,3,...$etc) and match it up with the graph.
2) Notice that the function is alternating between $\frac {1}{n}$ and $-\frac {1}{n}$, so graphing both of those functions will give a good idea of what the sequence looks like.
