I believe the correct answer would be strong/strength, because fort means strength.
<span>Napoleon's army was badly outnumbered, his best men were lost in his devastating invasion of Russia.</span>
The correct answer is - A war between the colonies and Britain.
After the Declaration of Independence and what it actually meant and encouraged the people in the colonies to do, the expected reaction from the British Empire was that it will try to use military force in order to keep the colonies under its control. And the expectations were true, as the British did launched a military campaign against the rebelling colonies, but the Americans were prepared for this and managed to withstand their ground and gained their desired independence, and that was a major blow for the British, especially from economic perspective.
Your answer is C. You share risks with others.