Answer:
The correct answer is: The British panicked when they were shot at.
Step-by-step explanation:
From sentence structure, it is obvious that the British was on the receiving end of the French and Indian attack. When referred to as "our advanced flank parties," it becomes clear as to which people panicked. The passage never mentioned the French and Indians other than to say that they attacked the British army. The attacked army then panicked, and "no order could be restored."