Concept: Article 21A deals with the Right to Education. It was inserted by the 86th Constitutional Amendment Act, 2002.
Step 1: Understand Article 21A.
Article 21A provides that the State shall provide free and compulsory education to all children of the specified age group.
\[
\text{Article 21A} = \text{Right to free and compulsory education}
\]
Step 2: Identify the age group.
The age group mentioned in Article 21A is six to fourteen years.
\[
6 \text{ years} \leq \text{Child's age} \leq 14 \text{ years}
\]
Step 3: Select the correct option.
Among the given options, the correct age group is six to fourteen years.
Therefore, the correct answer is option (D).