Based on an in-depth analysis of the philosophical and structural nature of Gordon Allport's 'Individual Traits' and Raymond Cattell's 'Source Traits' under personality trait theories, if a psychologist identifies the underlying, fundamental, and permanent dispositions hidden within an individual (such as the factors measured by the 16PF questionnaire) to understand their behavior, and concurrently studies the tripartite classification of traits proposed by Allport—namely Cardinal, Central, and Secondary—which of the following statements is most authentically true regarding both theories?

Gordon Allport adopted an 'idiographic' (individual) approach to the study of personality and divided traits into cardinal, central, and secondary categories, where 'cardinal' traits are extremely dominant and direct an individual's entire life.

In contrast, Raymond Cattell adopted a 'nomothetic' (universal) approach and utilized the statistical technique of Factor Analysis to discover 16 underlying fundamental 'source traits' of personality beneath the surface, subsequently developing the 16PF (16 Personality Factor Questionnaire).

Therefore, option (a) provides the most accurate and authentic analysis of the scientific and structural nature of both theories.