Hey there! I'm happy to help!
Tecumseh is famous for a curse he put on U.S. Presidents elected in years that that are multiples of 20. U.S. Presidents elected in those years are cursed to die while in office.
This started because he was defeated William Henry Harrison in battle, who was eventually elected the 9th U.S. President and died just around 40 days after being elected.
During the War of 1812, the British were fighting against the Americans. Tecumseh was the leader of the Shawnee tribe, and there were also fighting against the Americans to prevent them from taking their land.
So, answers B and D are incorrect because they imply that the Shawnee are against the British or on the side of the Americans, which is incorrect.
A is incorrect because Tecumseh was a chief. He wouldn't simply show the British where the camps were. He wants to fight against them with the British! So, the correct answer is C. He joined the British Army in hopes of pushing American settlers away from tribal lands.
Have a wonderful day and keep on learning! :D