An amplitude modulated signal consists of a message signal of frequency $1 \text{ kHz}$ and peak voltage of $5 \text{ V}$,modulating a carrier frequency of $1 \text{ MHz}$ and peak voltage of $15 \text{ V}$. The correct description of this signal is

• A
  $5[1+3 \sin (2 \pi 10^6 t)] \sin (2 \pi 10^3 t)$
• B
  $15[1+\frac{1}{3} \sin (2 \pi 10^3 t)] \sin (2 \pi 10^6 t)$
• C
  $[5+15 \sin (2 \pi 10^3 t)] \sin (2 \pi 10^6 t)$
• D
  $[15+5 \sin (2 \pi 10^6 t)] \sin (2 \pi 10^3 t)$