From the options given below choose the part that has an error:

A stopped clock (A) / is right (B) / twice in a day (C) / No error (D)

Correct option is C

• The sentence is: A stopped clock is right twice in a day. We need to find the grammatical error.
• The phrase twice in a day in part C is incorrect. The standard English expression is twice a day, meaning two times per day.
• A stopped clock (A) and is right (B) are grammatically correct.
• The correct sentence should be: A stopped clock is right twice a day.
• No other errors are present, so the error is in part C.
• Thus, C is the correct answer due to the incorrect preposition.