Which act among the following is both illegal and unethical?

The act of spreading false rumors about a competitor's product is both illegal and unethical for several reasons. Legally, this behavior can constitute defamation or disparagement, which involves making false statements that can damage a competitor's reputation and business. Such actions can lead to legal consequences, including lawsuits for damages if the competitor seeks to protect their reputation and market position.

From an ethical standpoint, spreading false information violates the principles of honesty and integrity in business practices. It undermines fair competition and can lead to a loss of trust not only between businesses but also with consumers who rely on accurate information to make purchases. This can create an unfair advantage not based on the quality of the products, but rather on deceitful tactics.

This differentiation makes the act of spreading false rumors distinctly illegal due to the potential for legal action, as well as unethical due to its disregard for truthfulness and fair play in business.