Which of the following crimes is always a felony under the law?

Voluntary manslaughter is categorized as a felony because it involves the intentional killing of another person with the absence of premeditation, often occurring in the heat of passion or as a result of provocation. This serious nature of the offense reflects society's recognition of the gravity of taking another person's life, even under circumstances that may mitigate the culpability compared to murder.

In contrast, the other options present lesser offenses or circumstances where the classification might vary. Assault and battery can sometimes be misdemeanors, especially if they do not result in significant injury. Driving under the influence is typically classified as a misdemeanor unless certain aggravating factors come into play, such as repeat offenses or causing serious injury. Theft of a bicycle can also be charged as a misdemeanor if the value of the bike falls below a certain threshold, typically outlined in statutory law.

Thus, voluntary manslaughter remains consistently classified as a felony, reflecting its serious implications and the legal system's broader view on violent crimes.