Mark's program was best described as 'clever' because it innovatively allowed computers to communicate when email was not popular. This indicates its utility and effectiveness in solving a communication problem. The other options do not accurately convey the program's significance. ;
Mark's program was best described as 'clever' because it provided an innovative solution for communication between computers at a time when email was not common. This reflects Mark's talent and effort in programming. Therefore, the chosen option is 'B. clever.'
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