The 3rd one. This is because if B is 45, and A is 90, then C is 45 because a Triangle is always 180 degrees. That means that BA is 12 ft. Using the Pythagorean Theorem, a^2 + b^2 = c^2, we can determine that 144 + 144 = 288, and the square root of 288 is 12 * 2
