💡 Detailed Explanation
The correct choice is 'おき' (forming '片付けておきましょう' - let's tidy up in advance). The grammar pattern '[Verb Te-form] + おく' (te oku) indicates performing an action beforehand in preparation for a future event. Sentence translation: 'Because guests are coming tomorrow, let's tidy up the room today in advance.' 'み' (to try doing), 'しまい' (to complete/regret), and 'いき' (to go on doing) do not fit this anticipatory context.