Answer: The sentence that uses Standard English is "The Joneses brought the baby home".
Step-by-step explanation: Standard English is the widely accepted form of the English language, that is to say that it is the dialect considered to be correct and the only one that must be used in formal contexts. The second sentence, "The Joneses brought the baby home", is the one that uses Standard English because it includes the standard form of the past tense conjugation of the verb "bring" ("brought"). On the other hand, "The Joneses brung the baby home" contains the non-standard and dialectical form of the past tense of "bring" ("brung"). "Brung" is part of the popular slang and, unlike "brought", it is used in informal contexts.