Certainly, rational appeals in advertising aimed at children are limited, as most advertisements use emotional and indirect appeals to psychological states or associations.
这句话的意思是rational appeals使用比较少，而 emotional and indirect appeals比较常用。所以作者是在比较rational appeals 以及 emotional and indirect appeals 的使用。
选项二Indirect appeals to children's psychological states or associations can limit the effectiveness of rational appeals in advertising.是说indirect appeals限制了rational appeals。而原句中并没有表达这层关系。
