Answer:
a) Trade, professional, and business magazines.
Explanation:
Trade, professional, and business magazines carry stories, features, and ads aimed at people in specific professions, and are distributed either by professional organizations or by media companies like Whittle Communications and Time Warner. Option b) is wrong because these magazines are produced by companies for their own employees, customers, and stockholders. Option d) is wrong because these magazines are provided to readers at no cost such as free airline magazines and hotel magazines.
