Speech balloons, also known as speech bubbles, dialogue balloons or word balloons, are a graphic convention used most commonly in comic books, comics and cartoons to allow words to be understood as representing the speech or thoughts of a given character in the story or events of the graphic novel or Comic.
According to the information presented before I would conclude that the main purpose of a speech bubble in a graphic novel is:
D) It illustrates internal thoughts.
Well, you need to give us the choices before we can give an exact answer but normally you can evaluate the tone by thinking about the context and meaning.
some examples of strong disapproval might be: "She's such a horrible person" or "I really hate this lamp it's ugly" The bolded words show the strong disapproval.
But most likely you should be able to find it by evaluating tone.
Answer:
Mike wants to have a quick visit with his grandmother, but he’s worried about how confused and upset she seems; so he stays and comforts her.
Explanation: