Hydrogenation of 1-Butene

In organic chemistry, addition reactions involve the addition of one or more atoms to a multiple bond. One common example of such a reaction is the addition of H₂ across a carbon-carbon double bond using a catalyst. This type of reaction is important in synthesizing various organic compounds. Consider the following statement about an addition reaction:

When 1-butene is treated with hydrogen gas (H₂) in the presence of a metal catalyst, which of the following products is formed?