A speech signal of 3 kHz is used to modulate a carrier signal of frequency 1 MHz, using amplitude modulation. The frequencies of the side bands will be
a. 1.003 MHz and 2.997 MHz
b. 3001 kHz and 2997 kHz
c. 1003 kHz and 1000 kHz
d. 1 MHz and 0.997 MHz