Context: Read the text about the blue dragon.
Do dragons exist? Believe it or not, the oceans contain a lizard-like creature called the blue glaucus or blue dragon. However, these "dragons" are not the fire-breathing beasts of fantasy. In fact, they are only about an inch long. Blue dragons are a type of sea slug.
Although these slugs are cuter than legendary dragons, you shouldn't let their squishy bodies fool you. These tiny creatures can be dangerous! Blue dragons eat poisonous sea creatures, such as Portuguese man-of-wars. The blue dragons store their prey's venom in their many "fingers." They can then use that stored poison to defend themselves. So, never touch a blue dragon—unless you want to get a painful and possibly serious sting.
Blue dragons have another way to stay safe from predators. They float on their backs so their bright blue bellies point upward. The blue blends in with the water, making it hard for predators flying overhead to see them. And predators swimming below will have trouble spotting the dragons' gray backs. The light color blends with the sunlight shining down through the water. This two-color effect is called countershading, and it's a good way to avoid getting eaten!
You might see blue dragons washed up on some beaches, but they usually drift on warm surfaces of the Atlantic, Pacific, and Indian Oceans. An air bubble in their stomach allows them to float for long periods of time. It is difficult for scientists to find these tiny creatures in the vast oceans. So, there is still much we don't know about them. What we do know, though, is that these beautiful dragons are full of surprising traits.
Based on the text, why are blue dragons dangerous?
A. Their strong fingers squeeze prey.
B. They have razor-sharp teeth and sharp fingers.
C. They use weapons to catch food.
D. Their sting is painful and can harm humans.
Select the correct answer from the given choices and respond with the letter of the chosen option.

D