In the theoretical paradigms of Second Language Acquisition (SLA), Stephen Krashen's Monitor Model and Noam Chomsky's nativist theory propose distinct cognitive and neurological mechanisms for language development. Consider the following complex propositions regarding the Monitor Model's five central hypotheses and nativist principles: I. The Acquisition-Learning Hypothesis posits that adult second language performance is driven entirely by conscious acquired competence, whereas subconscious learned knowledge serves exclusively as a 'monitor' or editor to alter output when there is sufficient time, focus on form, and knowledge of the rule. II. The Natural Order Hypothesis asserts that grammatical structures are acquired in a predictable, developmental sequence across second language learners regardless of their native language background, and this innate developmental sequence is largely impervious to deliberate classroom instructional sequencing. III. The Input Hypothesis maintains that language acquisition occurs only when learners are exposed to comprehensible input that is slightly beyond their current level of linguistic competence, formally represented as $i + 1$, where $i$ denotes the acquired linguistic level and $+ 1$ represents the next structural increment. IV. The Affective Filter Hypothesis claims that internal emotional variables such as high anxiety, low self-confidence, and lack of motivation raise the affective filter, creating a psychological block that prevents incoming comprehensible input from reaching the language acquisition device or the internal processing system. Identify the option that correctly evaluates the linguistic and pedagogical validity of propositions I, II, III, and IV.