What is one characteristic of a common carrier?

A common carrier is defined by its obligation to provide services to all customers on a non-discriminatory basis. This means that they must offer their services to anyone who wishes to use them, without bias or favoritism. This impartiality ensures that the carrier cannot selectively provide services based on individual customer profiles or perceived value, thus promoting fairness and accessibility in communication services.

The other options do not align with the definition of a common carrier. Focusing exclusively on high-value clients or specializing in one specific type of communication suggests a selective approach that is contrary to the fundamental principles of common carriage. Similarly, restricting access based on user ability does not fit the model, as common carriers are required to be open to all users regardless of their background, ensuring a level playing field in the marketplace.