Structure of a NAND gate (functional view): Evaluate the claim: “A NAND gate is built by connecting an AND gate and an OR gate in series with each other.” Decide whether this structural description is accurate.

Introduction / Context:
In introductory courses, learners sometimes try to infer complex gates as series combinations of simpler ones. It is important to separate functional equivalence from specific internal transistor-level realizations. The statement under test claims that a NAND equals an AND followed by an OR in series, which would imply a specific functional cascade.

Given Data / Assumptions:

• NAND’s Boolean definition is Y = NOT(A · B).
• “AND then OR in series” suggests a cascade that does not include an inversion stage unless added.
• Standard gates are considered functionally, not at transistor topology level.

Concept / Approach:
A NAND is the inversion of an AND: take an AND function and invert its output. An “AND then OR” cascade is neither required nor functionally equivalent to a single NAND. The minimal functional representation is AND followed by NOT (an inverter) or, equivalently, OR with inverted inputs (by De Morgan). None of these is “AND then OR” in series.

Step-by-Step Solution:

Verification / Alternative check:
De Morgan: Y = NOT(A · B) = (NOT A) + (NOT B). This shows an OR combining inverted inputs—not “AND then OR” serial connection.

Why Other Options Are Wrong:
“Correct” conflicts with Boolean definitions. Wired-logic and RTL/CMOS distinctions do not change the functional truth that NAND is AND plus inversion, not AND then OR.

Common Pitfalls:
Confusing series/parallel transistor networks with symbolic gate-level blocks; overcomplicating with unnecessary gates.

Final Answer:
Incorrect