Identify the structure

The given molecule is: $\mathrm{C^1H_2 = C^2 = C^3H - C^4H_3}$

This is an allene-type system at carbons 1, 2, and 3, followed by a single-bonded carbon 4.

Find hybridization of each carbon

Carbon 1

Carbon 1 is in the group $\mathrm{CH_2}$ and is double-bonded to carbon 2: $\mathrm{C^1H_2 = C^2}$

Around carbon 1, there are:

• one double bond to carbon 2
• two single bonds to two hydrogens

So, total regions of electron density = 3. Therefore, hybridization of carbon 1 is: $\boxed{sp^2}$

Carbon 2

Carbon 2 is the central carbon in: $\mathrm{C^1 = C^2 = C^3}$

It forms:

• one double bond with carbon 1
• one double bond with carbon 3

Thus, it has 2 regions of electron density and a linear arrangement. Therefore, hybridization of carbon 2 is: $\boxed{sp}$

Carbon 3

Carbon 3 is: $\mathrm{= C^3H - C^4H_3}$

It has:

• one double bond with carbon 2
• one single bond with hydrogen
• one single bond with carbon 4

Total regions of electron density = 3. Therefore, hybridization of carbon 3 is: $\boxed{sp^2}$

Carbon 4

Carbon 4 is a methyl carbon: $\mathrm{-C^4H_3}$

It forms:

• one single bond with carbon 3
• three single bonds with hydrogens

Total regions of electron density = 4. Therefore, hybridization of carbon 4 is: $\boxed{sp^3}$

Collect the results

Hybridizations of carbon 1, 2, 3, 4 are: $\boxed{sp^2,\ sp,\ sp^2,\ sp^3}$

Match with options

This corresponds to: $\boxed{\text{A}}$

Comparison with stored correct answer

Stored correct answer: A

Our derived answer: A

Hence, they agree.