Answer:
The correct answer is B) A flying boat floats on its fuselage.
Step-by-step explanation:
Contrary to a floatplane, a flying boat touches the water with its fuselage or body. Since this fuselage is essentially a large, hollow hull, it allows for stability even when the sea is rough (with the help of two small floats underneath the wings). On the other hand, a floatplane floats thanks to its two pontoons or long floats. Its body doesn't touch the water, which is why A) is incorrect.
C) is incorrect because both of these vehicles are considered amphibious, which means that they can operate on land and on water. D) is incorrect because the text says very clearly that flying boats are "usually larger [...] than floatplanes are.