Select the option that can be used as a one-word substitute for the given group of words. Loud enough to be heard.

Correct — D. Audible is the adjective for a sound loud enough to be heard, built from Latin audire ('to hear') plus -ible, the ending that means 'able to be'.

That ending is the trigger. The definition is passive — loud enough to be heard — so the substitute has to be an adjective in -ible or -able, and option (d) alone has that shape.

Why the others are wrong

• (a)
  Audit — Audit is an official examination of accounts. It does share the hearing root (Latin auditus, 'a hearing'), but it names the inspection, not the loudness of a sound.
• (b)
  Audacity — Audacity is a noun meaning boldness or nerve, from Latin audere, 'to dare'. A definition beginning 'Loud enough to be…' needs an adjective, not a noun.
• (c)
  Audacious — Audacious is the adjective of that same daring root — willing to take bold risks. It describes courage, not volume.

A one-word substitute item is a definition read backwards, and the wording tells you the word class before you know the word. 'A person who…' wants a noun; 'Loud enough to be…' wants an adjective.

The definition here is passive, and English marks 'able to be X-ed' with -ible or -able: audible, edible, legible, visible. Roughly, -ible sits on Latin stems that no longer stand alone in English, while -able sits on whole English words such as readable and drinkable.

Key facts

• Audible means able to be heard, from Latin audire.
• Audacious and audacity come from Latin audere, to dare.
• The -ible and -able endings carry a passive sense: able to be heard, eaten or read.
• Audit names an official examination of accounts.

Common traps

• Picking Audacious because it looks like the hardest word on offer.
• Choosing Audit on the shared aud- root without checking the meaning.
• Answering with a noun when the definition calls for an adjective.

No directly related past PYQ was found.