Given below are sentences that use discourse markers/expressions to make them complete. Identify the most appropriate discourse marker and mark your answer accordingly on the Answer Sheet.

__________, if the referee points his fingers, this indicates that someone has done something wrong.

The discourse marker 'Briefly' is used to introduce a concise explanation or summary. In the given sentence, it appropriately introduces a short explanation of a referee's action. 'On the contrary' requires a preceding contrasting statement. 'As regards' must be followed by a noun phrase to introduce a topic. 'Whatever more' is grammatically incorrect in this context.

Thus, 'Briefly' is the most appropriate choice to complete the sentence.

Answer: Briefly