In advanced English syntax, subject-verb agreement (or concord) is governed by structural hierarchy, semantic feature percolation, and coordinate constraints. Consider the following four complex propositions regarding subject-verb agreement: I. When two singular subjects are joined by correlative conjunctions such as *'either... or'* or *'neither... nor'*, the verb agrees strictly with the nearer subject in person and number according to the principle of proximity (e.g., *'Neither the professor nor her research assistants were present'*). II. Collective nouns denoting a single unified body (such as *'committee'*, *'faculty'*, *'family'*) invariably take a singular verb across all dialects of English, and intentional shifts to plural agreement based on notional concord (cadence of individual members acting independently) are strictly ungrammatical in formal standard registers. III. When a singular subject is modified by post-modifying prepositional phrases introduced by expressions of accompaniment such as *'along with'*, *'together with'*, *'as well as'*, or *'in addition to'*, the grammatical number of the head noun solely determines verb agreement, ignoring the nominal complement inside the phrase (e.g., *'The director, along with the entire board members, was scheduled to arrive'*). IV. Quantifying expressions involving fractions or percentages of a countable entity take a singular or plural verb depending strictly on the countability and number of the *of-phrase* complement (e.g., *'Two-thirds of the manuscript was completed'* versus *'Two-thirds of the chapters were revised'*). Identify the option that correctly evaluates the grammatical and syntactic validity of propositions I, II, III, and IV.