Bradford believed God punished a sailor who mistreated the Puritans.
It implicitly states that Greta does not like her gift because she does not actually say it.
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.
Answer:
I'd say quotation marks and bold or what you have selected which would be italics