Digital reliability principle: Computer ICs operate reliably because digital logic is based on a design paradigm that uses _____ states (levels) rather than many analog levels.

Introduction / Context:
Digital integrated circuits achieve robustness by encoding information with a small number of discrete levels—most commonly two: logic 0 and logic 1. This binary (two-state) approach provides noise margins and regenerative switching, which together make digital systems tolerant of moderate disturbances and component variation.

Given Data / Assumptions:

• Digital ICs use Boolean logic with well-defined thresholds.
• The question highlights the reliability benefit of discrete states.
• Two-state design underpins error-resistant computation and storage.

Concept / Approach:
By separating valid logic levels with thresholds and hysteresis (in some gates), digital circuits filter small analog variations. Transistors switch between saturation/cutoff or strong/weak inversion regions to produce rail-to-rail outputs. As long as signals remain within noise margins, computation remains correct despite supply variation, crosstalk, or temperature drift.

Step-by-Step Solution:
Recognize that binary encoding = two discrete states.Link discrete states to noise immunity and reliable switching.Select “Two-states” as the defining reliability paradigm.

Verification / Alternative check:
Specifications list VOH/VOL and VIH/VIL levels and define noise margins ensuring predictable logic behavior.

Why Other Options Are Wrong:
“Top-bottom,” “system,” and “two-stage” do not describe the fundamental binary nature of digital logic.

Common Pitfalls:
Confusing “two-stage” amplifier topology with “two-state” logic; they are unrelated concepts.

Final Answer:
Two-states.