What is the IUPAC name for a four-carbon chain with a triple bond?

The correct IUPAC name for a four-carbon chain with a triple bond is butyne. In organic chemistry, the suffix "-yne" is used to indicate the presence of a triple bond between carbon atoms. The prefix "but-" indicates that there are four carbon atoms in the longest continuous chain.

For butyne, since it has four carbons and a triple bond, it can specifically be named as either 1-butyne or 2-butyne, indicating the position of the triple bond. If the triple bond starts at the first carbon, it's called 1-butyne. If it starts at the second carbon, it’s referred to as 2-butyne. However, without additional information, simply naming it butyne suffices to convey that a triple bond is present in a four-carbon chain.

Other options like butene refer to compounds with a double bond, butanol refers to a four-carbon alcohol with a hydroxyl (-OH) group, and butanamine refers to a four-carbon amine. Thus, these names do not correspond to the required structure featuring a triple bond.