(A) - (IV) obligatory → "It is obligatory for each citizen to pay income tax" - obligatory means legally or morally required/mandatory.
(B) - (III) adamant → "He is so adamant that there is no point trying to convince him" - adamant means refusing to be persuaded or change one's mind.
(C) - (I) benevolent → "This benevolent business house has built many schools and hospitals" - benevolent means well-meaning, kind, and charitable.
(D) - (II) respite → "There is no respite from the continuing cold spell" - respite means a short period of rest or relief from something difficult.
Hence, Option 1: (A) - (IV), (B) - (III), (C) - (I), (D) - (II) → All words fit contextually and grammatically in their respective sentences, with obligatory indicating legal duty, adamant showing stubbornness, benevolent describing charitable nature, and respite meaning relief or break → correct