True or false:

(a) A digital signal is a continuously changing voltage.

(b) A digital signal is a sequence of numbers that represent an analog signal. When processing an analog signal, the output may be distorted due to: 

(a) Quantization error when converting analog to digital 

(b) Not sampling the original signal frequently enough

(c) Temperature variation in the processor components

(d) The high-frequency components associated with sudden changes in voltage out of the DAC

(e) Electrical noise on the power supply

(f) Alias signals introduced by the digital system