Which statement best contrasts analog and digital signals?

• A. Analog signals are discrete; digital signals are continuous.
• B. Digital signals are discrete; analog signals are continuous.
• C. Analog signals are continuous; digital signals are discrete.
• D. Both signals are continuous and vary gradually.

Answer: (C)

The key idea is continuity versus discreteness in how signals behave over time. An analogue signal can take any value at any moment, changing smoothly without jumps, so it’s continuous. A digital signal represents information with a finite set of separate values and only changes at specific moments in time, making it discrete. That’s why analog signals are continuous while digital signals are discrete. When we convert real-world signals to digital, we sample them at intervals (discrete time) and assign each sample to a limited number of levels (discrete values), which is the reason digital signals aren’t continuous. The other options either swap these ideas or claim both signals are always continuous, which isn’t accurate.