Final answer:
Price transparency is the correct answer to the student's question, indicating a market condition where all participants have access to the same pricing information in e-commerce.
Step-by-step explanation:
The term that means all market participants can trade at the same price in e-commerce is price transparency. This concept is vital in markets, especially in perfect competition, where many sellers offer identical products, sellers as well as buyers are well informed about products, and there is free entry and exit from the market. In such a market, price transparency ensures that all parties have full information on product prices and quality, leading to an equilibrium price that reflects the true market value of the goods or services offered.