Adverbial placement in English can significantly alter the focus and scope of a sentence, especially regarding negative inversion and focus adverbs like "only." Regarding the syntactic constraints of adverbials in formal written English, mark T for True or F for False:

(__) Negative adverbials such as "seldom" or "under no circumstances" trigger subject-auxiliary inversion when placed in the initial position of a clause.
(__) Focus adverbs should be placed immediately before the constituent they modify to avoid semantic ambiguity in formal registers.
(__) Adverbs of frequency must be positioned before the auxiliary verb "be" in all indicative sentences regardless of the presence of other modals.
(__) Viewpoint adverbs like "theoretically" function exclusively as adjuncts and are strictly prohibited from appearing in the initial sentence position.

After analysis, choose the alternative that presents the CORRECT sequence: