Final answer:
The line of dialogue that provoked Squeaky's decision to argue with Gretchen, Rosie, and Mary Louise on page 3 is A. Mary Louise asks Raymond, "What grade you in now, Raymond?"
Step-by-step explanation:
The key dialogue that triggers Squeaky's decision to argue is Mary Louise's question directed at Raymond. Squeaky is fiercely protective of her brother Raymond, and any inquiry about his abilities or grade level seems to irritate her. Mary Louise's question appears to challenge Raymond's capabilities or place him in a potentially judgmental light, prompting Squeaky to respond defensively and engage in an argument.
Squeaky's strong sense of responsibility for Raymond, as well as her determination to shield him from any perceived disrespect or judgment, underscores her character's protective and caring nature. This moment in the dialogue catalyzes Squeaky to assert herself and defend her brother against any implied criticism or doubt.
In conclusion, the specific line of dialogue, "What grade you in now, Raymond?" from Mary Louise, is the trigger that provokes Squeaky's decision to argue with Gretchen, Rosie, and Mary Louise on page 3. This moment illuminates the depth of Squeaky's commitment to her brother and her readiness to confront any perceived challenges to his capabilities.