💡 Detailed Explanation
The correct choice is 'たままで' (forming 'つけた状態で維持して' - left X in the state of). The grammar pattern '[Verb Past Form] + ままで' indicates performing an action or starting a state and leaving it as is while doing something else. Sentence translation: 'I fell asleep with the lights left on, and caught a cold.' 'ただけで' means just/only.