In the theoretical framework of second language acquisition and cognitive linguistics, Noam Chomsky's nativist paradigm and Stephen Krashen's Monitor Model offer distinct explanations for how human beings process, internalize, and utilize language. Consider the following four advanced propositions regarding language acquisition and learning: I. Chomsky's nativist hypothesis posits that human infants are biologically endowed with an innate Language Acquisition Device (LAD) containing universal grammar principles, which helps resolve the 'poverty of the stimulus' dilemma by enabling children to acquire complex syntax effortlessly despite degenerate or limited primary linguistic input. II. Krashen's Acquisition-Learning Hypothesis maintains a strict non-interface position, asserting that subconscious 'acquisition' and conscious 'learning' are distinct cognitive processes, and that explicitly learned grammar rules can readily convert into acquired linguistic competence through intensive mechanical drilling and rote memorization. III. Krashen's Affective Filter Hypothesis contends that emotional variables such as high anxiety, low self-confidence, and defensive motivation can raise the affective filter, creating a psychological mental block that prevents comprehensible input from reaching the language acquisition faculties. IV. Krashen's Natural Order Hypothesis suggests that grammatical structures and morphosyntactic items are acquired in a predictable, invariant developmental sequence across diverse learners, independent of the explicit instructional sequencing established by a syllabus or native language background. Identify the option that correctly evaluates the theoretical, psycholinguistic, and pedagogical validity of propositions I, II, III, and IV according to standard language acquisition theory and Second-language acquisition principles.