Given the periodic function $f(x)=x^2$ on $-2x2$ with $f(x)=f(x+4).$ The coefficient $A_2$ of the Fourier series associated with the above given function can be computed as:

a$)\frac{4}{{}^2}$

b$)2$

c$)\frac{16}{{}^2}$

d$)\frac{1}{4}$

e$)$ None of the other options are correct