Answer: traded on material non public information
Explanation: Material non public information refers to the information that is not made available to the general public by the firm and can influence the decision making of a general investor regrading buying or selling of the stock.
Insider trading refers to the practice in which the top level employees of an organisation trade the stock of the company on the basis of the information they possess that are not made available to the public yet.
Hence we can conclude that Brianna is liable for insider trading as she had the inside information that the dividends of the company are gonna increase.