An investment adviser representative engages in a policy of placing block trades for securities that he wishes to purchase, which are allocated to both the adviser's proprietary account and the adviser's customers' accounts. which statement is true? a. this is an unethical business practice under nasaa rules because advisers are not permitted to trade for their own proprietary accountsb. this is permitted if it leads to lower commission costs and higher potential rates of returnc. this is an unethical business practice because the adviser is breaching his fiduciary duty to the customerd. this is permitted if the administrator does not have a rule prohibiting the adviser from engaging in block trading