What type of services are compelled by an outside source or involve penalties for non-compliance?

The correct answer pertains to services that are required due to external regulations or laws, which includes penalties for not fulfilling them. This definition aligns with the concept of compulsory services, such as those mandated by governmental or legal authorities.

The term often used for such services is "mandatory" or "obligatory." These services generally do not allow for personal choice; they are enforced by an outside source, ensuring compliance through potential consequences. This is critical in ensuring that all members of society contribute to communal goals or adhere to laws designed to promote public welfare.

In contrast, the other options refer to types of service that either offer incentives or are entirely voluntary, hence lacking the element of compulsion. Voluntary community work and incentivized services suggest participation based on personal choice or benefits, while mandatory volunteering introduces a notion that may imply the expectation of participation without monetary incentives but still does not capture the enforcement element that comes with penalties for non-compliance.