There are a total of 18 employees in a unit. Due to the lack of scientific management, the phenomenon of unreasonable people and unreasonable distribution is very serious. The salary is only divided into two categories: higher and lower. There are many low-paid people who are not clerks. It is a little gratifying that among those who are not clerks, only a few people have high salaries; in addition, there are still clerks with low wages. Recently, Zhang He Xiao Wang left the unit, but the aforementioned structure of the unit's personnel has not changed as a result. Based on this, it can be inferred that Xiao Zhang or Xiao Wang originally could not be in the unit? ['High-paying clerks.', 'Low-paid officers.', 'Highly-paid officers.', 'Low-paying clerks.']