Detailed Video Solution, with Complete Analysis: https://youtu.be/ks2tg5UaQ08
NOTE that 3-inputs XNOR gate is NOT same as 3-inputs XOR gate. XNOR gate is ALWAYS Complement of XOR gate.
A Very Important NOTE:
$XNOR$ gate with inputs $A,B,C$ is NOT same as $A \odot B \odot C .$
$XNOR-n$ gate is defined as Complement of $XOR-n$ gate.
NOTE that:
$a \odot b \odot c = a \oplus b \oplus c$
BUT $XNOR-3 \,\, gate \neq XOR-3 \,\, gate$
The exclusive‐NOR gate is the complement of the exclusive‐OR gate, as indicated by the small circle on the output side of the graphic symbol.
Detailed Video Solution, with Complete Analysis: https://youtu.be/ks2tg5UaQ08
3 Inputs XNOR gate, Complete Analysis: https://youtu.be/uAadNn38oFo
XOR & XNOR functions: https://www.youtube.com/watch?v=-30dUjh6Qv4
After watching THIS video solution, Solve this GATE EC 2010 question: https://ec.gateoverflow.in/1953/gate-ece-2010-question-12