Restriction of competition refers to the behavior of the government and its subordinate departments, public enterprises or other operato with a dominant position in accordance with the law to hinder or even completely prevent or exclude market entities from competing.
According to the above definition, which of the following options is restriction of competition?
A city's quality supervision and management agency recommended a certain brand of phone, and pointed out that the quality of the phones produced by several manufacturers had problems, and requested all work units not to buy them.