What type of carrier provides transportation services without charging a fee?

The question is focused on identifying a type of carrier that offers transportation services without a fee. Private carriers are typically companies or individuals that transport goods or services primarily for their own use and do not provide services to the general public for a fee. Their transportation operations are generally based on internal needs rather than on a business model that relies on charging for services.

In contrast, public carriers, common carriers, and freight forwarders operate with a business model that usually involves charging fees for their transportation services. Public carriers and common carriers serve the general public and are regulated to provide services at set rates, while freight forwarders act as intermediaries to organize the shipping of goods and charge for their services. Since private carriers focus more on serving their own logistical needs rather than providing free services to others, this is why they are viewed as the correct answer in this context.