In a certain socialist country, party members earn twice as much as non-party members do. But party members happen to work in the businesses that generally have higher wages. Non-party members who also work in these particular businesses earn about as much as party members. Therefore, higher incomes do not necessarily result from the connection with the party.

Which of the following, if true, most seriously weakens the argument above?

【选项】Besides wage increases, party members also receive other benefits.