Select the most appropriate ‘one word’ for the expression given below.
Someone who can detect truth when it is being told, with the ability itself being referred to as truthsense.

Correct option is C

The correct one-word substitution is (c) Truthsayer.

Given expression – Someone who can detect truth when it is being told (truthsense):

• This refers to a person strongly associated with truth—someone who recognises or speaks what is true.
• Among the given options, truthsayer is the nearest appropriate term.

Correct answer word – Truthsayer:

• Meaning: A person who speaks the truth; one who tells or reveals truth. (Hindi meaning: सत्य कहने वाला / सत्य बताने वाला)
• Example: The whistleblower was seen as a truthsayer by the public.

Meanings of all the other given options:

• Trueman – Not a standard word for this meaning (मानक शब्द नहीं).
• Trueness – The quality of being true (सत्यता); it is an abstract noun, not a person.
• Trueborn – Of noble or legitimate birth (वैध/उच्च जन्म); unrelated to detecting truth.

So the correct answer is (c)