Select one: Select one: A. A negative external effect occurs when a person's action imposes a cost on others and this cost is not taken into account by the individual taking the action. B. A positive external effect occurs when a person's action imposes a cost on others and this cost is not taken into account by the individual taking the action. C. A negative external effect occurs when a person's action confers a benefit on others and this benefit is not taken into account by the individual taking the action. D. A negative external effect occurs when a person's action imposes a cost on others and this cost is taken into account by the individual taking the action. E. A positive external effect occurs when a person's action confers a benefit on others and this benefit is taken into account by the individual taking the action