what do we call black substance that stick to teeth and give ways of eliminating the substance. Thank you​

Jamal reads an interesting article about the use of apps for handheld devices in cognitive therapy. he finds severa therapists use this approach and the results of the approach. jamal decides to recommend this technique for one decision making does jamal use in this scenario? a. ethical decision making evidence-based decision making c. shared decision making d. rule-based decision making e.metacognitive decision making