Which of the following best describes insider trading?

Insider trading refers to the buying or selling of stocks based on non-public, material information about a company. The practice is considered unethical because it provides an unfair advantage to those who possess this insider information over regular investors who do not have access to such details. This violation of trust undermines the integrity of the financial markets, making "B" the most accurate description.

In contrast, the other choices do not accurately capture the essence of insider trading. The first option describes legal trading practices, which do not involve the misuse of private information. The third option refers to a legitimate investment strategy that is based on market analysis and publicly available information, focusing on long-term gains without any unethical implications. The fourth option suggests a marketing tactic, which is unrelated to the concept of trading informed by proprietary company data. Thus, "B" best encapsulates the unethical nature of insider trading.