Correct option is C
• Explanation: The passage clearly states that autism is most prevalent among school-aged children between 5 and 14 years. This directly answers the question about the main age group.
• Correct answer word – between 5 to 14
Meaning: age group where autism cases are highest
Example: Most students in this class are between 5 to 14 years old.
Meanings of other options:
• between 5 to 10 – incomplete range, not mentioned
• between 3 to 14 – incorrect lower range
• between 1 to 10 – not supported by passage