Find a Fourier series expansion of the periodic function f(t)=-2t, -1t1 f(t) = f(t+2) Select one: O a. O b. 0 . O d. f(t)= n=1 F(t) = 4(-1)"1 77=1 4(-1)"+1 n (t) = 4 (-1)", 77=1 00 f(t)= 77=1 , 4(-1)" n sinnt sin nat - sin nat -sin nt