Step 1: Understanding Fundamental Rights.
The abolition of untouchability is included under the Fundamental Rights, specifically within the Right to Equality (Articles 14–18). These rights ensure equality before the law and prohibit discrimination.
Step 2: Identifying the Relevant Article.
Article 17 explicitly states that untouchability is abolished and its practice in any form is forbidden. It also makes enforcement of any disability arising out of untouchability an offence punishable by law.
Step 3: Checking the Options.
(A) Article 15 prohibits discrimination on various grounds but does not abolish untouchability.
(B) Article 16 deals with equality of opportunity in public employment.
(C) Article 17 is the only article that abolishes untouchability.
(D) Article 18 abolishes titles, not untouchability.
Step 4: Conclusion.
Therefore, the article that abolishes untouchability is Article 17.