Which of the following psychological statements is most authentic and scientifically valid regarding the ratio-based scientific measurement of 'Mental Age' and 'Chronological Age' within the modern conceptual framework of 'Intelligence Quotient' (IQ) propounded by Alfred Binet and Theodore Simon and refined by William Stern and Lewis Terman, along with the actual psychological implications of Deviation IQ, homogeneous grouping for exceptional children (gifted and mentally challenged), and the scientific management of remedial teaching in classroom instruction?

Detailed Explanation

This question examines the deep theoretical underpinnings of intelligence measurement, specifically focusing on the transition from Ratio IQ to Deviation IQ:

• Ratio IQ Limitation: William Stern formulated Ratio IQ as \((MA / CA) \times 100\). However, a major limitation is that mental growth plateaus in late adolescence, while chronological age keeps increasing, leading to distorted IQ scores for adults.
• Deviation IQ: To resolve this, modern psychometrics uses Deviation IQ (popularized by Wechsler), which compares an individual's score against their age peer group using standard deviation, ensuring statistical accuracy across all age groups.

Therefore, Option A correctly identifies the statistical and psychological flaw of traditional ratio IQ and the advantage of deviation IQ.