Select the most appropriate option to fill in the blank. In the early autumn fierce fighting took place, the __________ Serbians bearing a prominent part.

gallant

The correct option to fill in the blank is gallant.

• Cowardly means showing a lack of courage. It is not the most appropriate word to use in this context, as it would suggest that the Serbians were not brave.
• Unabashed means showing no shame or embarrassment. It is not the most appropriate word to use in this context, as it does not specifically refer to the Serbians' bravery.
• Bore means to be tedious or boring. It is not the most appropriate word to use in this context, as it does not specifically refer to the Serbians' bravery.