Three identical rectangles are put together to form rectangle ABCD, as shown in the figure below. Given that the length of the shorter side of each of the smaller rectangles 5 feet, what is the area in square feet of rectangle ABCD?
[asy]draw((0,0)--(0,10)--(15,10)--(15,0)--(0,0));
draw((0,5)--(10,5));
draw((10,0)--(10,10));
label("A",(0,0),SW);
label("B",(15,0),SE);
label("C",(15,10),NE);
label("D",(0,10),NW);
dot((0,10));
dot((15,0));
dot((15,10));
dot((0,0));
[/asy]
<spanclass=′latex−bold′>(A)</span>45<spanclass=′latex−bold′>(B)</span>75<spanclass=′latex−bold′>(C)</span>100<spanclass=′latex−bold′>(D)</span>125<spanclass=′latex−bold′>(E)</span>150