Please explain why answer was chosen

QUESTION 1: Select the correct statement(s) regarding communications.

a. transmission power must be sufficient to overcome both signal attenuation and noise

b. EM noise products that exist at the same frequencies as the signal must be considered when determining if sufficient signal energy will exist at the receiver

c. signal frequency bandwidth is related to communications channel capacity

d. all statements are correct

QUESTION 2:Select the correct statement(s) regarding the signal-to-noise ratio (SNR).

		a. SNR represents the ratio of transmit signal power over the noise power of all sources including thermal, impulse, IM, CCI, and crosstalk noise
		b. the noise (i.e., noise floor) in the signal-to-noise ratio, represents thermal noise
		c. the noise power, in the signal-to-noise ratio, occupies a narrow band in the frequency domain
		d. all of the above are correct statements

QUESTION 3:When two transmitters operate on the same frequency in close proximity to each other, cochannel interference can occur.

True False

QUESTION 4: Crosstalk noise can occur in either guided or unguided communication channels.

True False