A telephone company in a certain place has started to provide consumers with electronic operator system services. However, the company's manual operators will not be reduced in the near future. Which of the following does not help explain the above phenomenon. ['The number of phones requiring human operator assistance has skyrocketed.', 'Although it has been tested, the new electronic operator system needs further adjustments to fully function.', 'If the manual operator is fired during the current contract period, the relevant party will be liable.', 'The efficiency of the new electronic operator system is similar to that of a manual operator.']