Find a power series representation for $f(x)=arctanx.$

Select one:

a$.x-\frac{x^3}{2}\frac{x^4}{4}-\frac{x^4}{6}$ dots

b$.1\frac{x^3}{3}\frac{x^4}{5}\frac{x^7}{7}$ dots

c$.x-\frac{x^3}{3}\frac{x^3}{5}-\frac{x^7}{7}$ dots

d$.-x$