Interpret the reaction

The question asks for the number of $sp^2$-hybridized carbon atoms in the major product $A$.

Since this is from hydrocarbons, the relevant idea is:

• Each carbon atom involved in a double bond is $sp^2$ hybridized.
• Carbon atoms in a triple bond are $sp$ hybridized.
• Saturated carbons are generally $sp^3$ hybridized.

Major product identification

In the given reaction, the major product $A$ contains one carbon-carbon double bond as the unsaturation in the final hydrocarbon product.

Count $sp^2$ carbons

A single $C=C$ bond has:

• 2 carbon atoms
• both are $sp^2$ hybridized

Therefore, number of $sp^2$ carbons in $A$ is $2$

Final answer

The major product $A$ has 2 $sp^2$ hybridized carbon atoms.