The most suitable word for the blank in this context is "consideration". So, the sentence should be: "Please take the above into consideration and let us know your decision as early as possible." This sentence suggests that you are asking the recipient to carefully think about or evaluate the information provided and make a decision based on it. "Consideration" implies careful thought and evaluation, which is appropriate in this context. "List" would not be suitable because it suggests a compilation of items rather than careful thought or evaluation. "Agenda" is related to a schedule or plan of action, which is not the focus here. "Arrangement" usually refers to the organization or setup of something, which is also not relevant to this request for consideration and a decision.
