(A) "wear one's heart on one's sleeve" means to openly display emotions and be completely frank → matches with (III) be completely frank and hide nothing from others
(B) "to sell someone down the river" means to betray or be disloyal to someone → matches with (IV) to betray someone
(C) "talk through one's head" (variation of "talk through one's hat") means to speak without knowledge or boastfully → matches with (II) to talk boastfully or irresponsibly
(D) "to take the bull by horns" means to confront a difficult situation directly and boldly → matches with (I) attack an opponent in a bold and direct fashion
Hence, Option 1: (A) - (III), (B) - (IV), (C) - (II), (D) - (I) → This correctly matches all four idioms with their meanings, showing proper understanding of these common English expressions → correct