Select the most appropriate option to improve the underlined segment in the given sentence. If there is no need to improve it, select ‘No improvement’.

But for their valour, they would have been defeated. 

The correct answer is 'No improvement'. 

Key Points

• The given question is grammatically correct. Here, the phrase 'But for' is correct. 
• When we use 'But for' it means If it hadn’t been for. 
• This makes 'but for' the equivalent of the third (remote) conditional where the main clause contains the would have construction. 
  • Example: But for (If I hadn't drunk) the glass of wine I had for dinner, I would have got the housework done.
• Therefore, the correct answer is Option 2. ​

Additional Information

• Third Conditional: The third conditional, also called the "Past Unreal" conditional is used to describe unreal situations in the past. It is often used to express regret about the past because the hypothetical situation that it describes is now impossible as a consequence of another past action. 
• The structure of it as follows:
  • If + past perfect, would + have + past participle. 
    • Example: If we had won, I would have been happy.