Final answer:
Charlie's soliloquies contribute to the overall plot by showing what he is thinking and why he continues to act as he does, even when his actions have poor results. They give insight into his character and his comically flawed understanding of the situation.
Step-by-step explanation:
Charlie's soliloquies are critical in revealing his thought process and reasons behind his actions in the script. They provide insight into his character, allowing the audience to understand Charlie's misguided confidence and his inability to recognize the actual effect of the cologne. Option A is correct; these monologues give a direct window into Charlie's thoughts, showing how he rationalizes the situation and plans his next steps, despite the obvious signs that his approach is not working. He mistakenly believes that by applying more cologne, he will become more attractive to the girls, which is humorously far from the truth.