What type of law is often enacted by legislation and is more specific in its purpose?

The correct choice is "Act." An act is a law passed by a legislative body, which has a specific purpose or intent. It is typically more comprehensive than a single section of law and is designed to address particular issues or regulate specific areas of behavior or activity. An act represents formal legislation and provides guidance on how laws should be applied, detailing requirements, rights, or duties for individuals or organizations.

In contrast, a statute may refer broadly to laws enacted by legislative bodies but can encompass a wider range of legislative instruments. An ordinance often pertains to local laws established by municipalities or local governing bodies, targeting community issues rather than systemic regulatory frameworks. A provision refers to a specific clause or section within a larger legal document or body of law, lacking the standalone authority or direct purpose that comes with an act.

Therefore, an act's specific focus and legislative origin make it the most suitable answer to the question about types of law that are enacted through legislation and possess a distinct purpose.