Given below are two statements: 

Assertion (A):  All the carbon atoms in  H2C = C = CH2  are sp2-hybridised.
Reason (R): In this molecule, all the carbon atoms are attached to each other by double bonds.

 

1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.

Hint: second carbon is sp hybridized
 
Hybridization can be determined by counting σ- bond
H2C3σ=C2σ=CH23σ
3σ-sp2 hybridisation
2σ-sp hybridisation
 In H2C=C=CH2, the central carbon is sp-hybridised whereas the terminal carbons are sp2-hybridised. Thus, the Assertion is false but the reason is true.