In advanced English tense-aspect morphology, temporal framing, habitual iteration, and future time projection exhibit rigorous structural constraints. Consider the following four advanced propositions regarding tenses and their correct usage: I. When an active sentence describes an incomplete state of affairs or an ongoing action that began in the past and continues into the present moment, standard English requires the present perfect continuous or present perfect simple tense combined with a duration adverbial introduced by 'since' or 'for' (e.g., 'The research team has investigated the anomalous radiation signatures for over three years'), rendering the simple past tense ungrammatical in this specific aspectual context. II. In complex narrative sequences involving multiple past events, the past perfect tense is strictly and invariably obligatory to mark every single past action, regardless of whether the sequential chronological order is already explicitly established by temporal connectors such as 'before', 'after', or 'then' (e.g., 'After the detective had arrived at the crime scene, he had examined the forensic evidence and had interrogated the prime suspect'). III. When expressing a future arrangement, official itinerary, or scheduled timetable in professional or formal discourse, the simple present tense can function as a futurate tense marker denoting fixed, invariable events (e.g., 'The international summit commences on Monday morning'), whereas spontaneous future intentions or immediate predictions require modal auxiliaries like 'will' or 'shall'. IV. In conditional clauses of the first type (open or probable future conditions), the protasis (if-clause) must employ the simple present tense to indicate future contingency, while the apodosis (main clause) utilizes the modal auxiliary 'will' or 'shall' combined with the base verb (e.g., 'If the meteorological department issues a severe weather warning, all coastal flights will be grounded immediately'). Identify the option that correctly evaluates the grammatical, syntactic, and semantic validity of propositions I, II, III, and IV according to standard English grammar and Grammatical tense principles.