In which of the following situations has there been no violation of nasaa rules? a. an agent omits mentioning a material fact necessary to make a presentation about a security not misleading, but the customer decides not to buy the securityb. an agent misstates a material fact to a customer when recommending a security, and the customer buys that security and enjoys a profitc. an agent makes a recommendation to a customer, disclosing all relevant information about the issue known to that agent and the customer buys that security and suffers a lossd. any of the above