Step 1: Understanding the Concept:
The question asks to identify the figure associated with a specific set of ethical principles for Public Relations, notably "Tell the truth."
Step 2: Detailed Explanation:
(1) Jean Piaget and (2) Lev Vygotsky: Both were seminal developmental psychologists, known for their theories of cognitive development in children. They were not public relations practitioners.
(4) Sigmund Freud: The founder of psychoanalysis, a clinical method for treating psychopathology. His nephew, Edward Bernays, is considered a father of PR, but Freud himself was not.
(3) Arthur W. Page: He is considered the "father of corporate public relations." As the first vice president of public relations for the American Telephone and Telegraph Company (AT \& T) from 1927 to 1947, he established a set of principles for ethical and effective PR. These are known as the Page Principles. The first and most famous of these is "Tell the truth." The principle "Manage for tomorrow" is also one of his seven principles, emphasizing the need to anticipate public reaction and eliminate practices that cause conflict.
Step 3: Final Answer:
The seven principles of Public Relations management, including "Tell the truth," were practiced and articulated by Arthur W. Page.