Since there are 12 inches in a foot, we need to convert the 8 inches to feet before adding it to the height of the tower.
8 inches is equal to 8/12 = 2/3 feet.
Therefore, adding the block will increase the height of the tower to:
114 + 2/3 = 114 2/3 feet
So the final height of the block tower is 114 2/3 feet, which is approximately equal to 114.67 feet.
Therefore, the answer is closest to 115 feet.