In $\mathrm{HC}\equiv \mathrm{C}-\mathrm{CH}{}_2-\mathrm{CH}=\mathrm{CH}-\mathrm{CHO}$, the numbers of $sp$, $s{p}^2$ and $s{p}^3$ hybridised carbon atoms, respectively, are

The two carbons of the triple bond are $sp$. The two alkene carbons and the aldehyde carbon (C=O) are $s{p}^2$, which makes three. The only saturated carbon is the $\mathrm{CH}{}_2$ group ($s{p}^3$), giving 2, 3, 1.