Business Consultant: Some corporations shun the use of executive titles because they fear that the use of titles indicating position in the corporation tends to inhibit communication up and down the corporate hierarchy. Since an executive who uses a title is treated with more respect by outsiders, however, use of a title can facilitate an executive's dealings with external businesses. The obvious compromise is for these executives to use their corporate titles externally but not internally, since even if it is widely known that the corporation's executives use executive titles outside their organization, this knowledge does not by itself inhibit communication within the corporation.

In the consultant's reasoning, the two portions in boldface play which of the following roles?

【选项】The first presents an obstacle to achieving a certain goal; the second presents a reason for considering that goal to be undesirable.