This question has multiple parts. Work all the parts to get the most points.

a How many $p$ atomic orbitals are in the conjugated system?

$4$

Correct

Each carbon of the conjugated pi system contributes one $p$ atomic orbital to the pi system. For $2,4-$hexadiene, $4$ carbons and $4p$ atomic orbitals make up the conjugated pi system.

b How many molecular orbitals describe the conjugated system?

$2$

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