Pick the most appropriate word to fill (i) in the given passage

Option Explanation Option 1: invariable ❌ Adjective – doesn't fit here; we need an adverb to modify the verb “are”. Option 2: invariably ✔️ Correct – adverb describing how people are guided (always or consistently guided by reason). Option 3: invariabily ❌ Incorrect spelling – not a valid word. Option 4: invariability ❌ Noun – refers to the state of being unchanging; doesn't fit grammatically.