In plotting line spectrum______

A)
a graph of |Fn| versus frequency is plotted
B)
a graph of the angle of Fn versus frequency is plotted
C)
a graph of complex number Fn versus frequency is plotted
D)
two graphs viz |Fn| versus frequency and the phase angle of Fn versus frequency are plotted

Correct Answer : Option (D) :   two graphs viz |Fn| versus frequency and the phase angle of Fn versus frequency are plotted