The signal obtained at the output of a microphone is of which type?

$A$ $100\,m$ long antenna is mounted on a $500\,m$ tall building. The complex can become a transmission tower for waves with $\lambda$ (approx) ........ $m$.

Television signals on earth cannot be received at distances greater than $100\, km$ from the transmission station. The reason behind this is that

$List-I$	$List-II$
$A.$ Facsimile	$I.$ Static Document Image
$B.$ Guided media Channel	$II.$ Local Broadcast Radio
$C.$ Frequency Modulation	$III.$ Rectangular wave
$D.$ Digital Signal	$IV.$ Optical Fiber

Choose the correct answer from the following options:

If $f_a$ and $f_f$ represent the carrier wave frequencies for amplitude and frequency modulations respectively,then

Modulation is a process of superposing