Final answer:
Carbon atoms 1 and 4 have tetrahedral shapes with sp³ hybridization, while carbon atoms 2 and 3 have linear shapes with sp hybridization.
Step-by-step explanation:
Carbon atoms 1 and 4 have four single bonds and are thus tetrahedral with sp³ hybridization.
Carbon atoms 2 and 3 are involved in the triple bond, so they have linear geometries and would be classified as sp hybrids.