Lindsie is painting on a canvas with dimensions of 3 ft by 4 ft. She wants to make a display model for a gallery that has twice the area of the original. How much should she increase the length and width by, if she wants to increase them by the same amount? Round your answer to the nearest tenth.
A. 10.4 feet
B. 1.4 feet
C. 3.4 feet
D. 8.4 feet