Option 1 -> (A)-(II) callous doesn't fit; (B)-(III) connotes is a verb, not the noun needed for skin hardening; (C)-(I) denotes is correct; (D)-(IV) callus is a noun, not the adjective needed.
Option 2 -> (A)-(III) connotes suggests emotional associations; (B)-(IV) callus is the hardened skin; (C)-(I) denotes indicates literal reference; (D)-(II) callous means emotionally insensitive - all correct.
Option 3 -> (A)-(III) connotes is correct; (B)-(IV) callus is correct; (C)-(II) callous doesn't fit grammatically; (D)-(I) denotes doesn't work as an adjective.
Option 4 -> (A)-(I) denotes is too literal for emotional associations; (B)-(IV) callus is correct; (C)-(II) callous doesn't fit; (D)-(III) connotes doesn't work as an adjective.
Hence, Option 2: (A) - (III), (B) - (IV), (C) - (I), (D) - (II) -> "Connotes" captures implied meaning vs "denotes" for literal meaning, while "callus" (noun for hardened skin) differs from "callous" (adjective for being insensitive) -> correct