The confusion often arises between "lay" and "lie." Here's a breakdown:

• "Laid" is the past tense of "lay," and it requires an object. For example, "He laid the book on the table."

• "Lay" is the past simple form of "lie" when it means to recline. For example, "After Jerry had made the bed, he lay on it."

So, in this context, the correct choice is "D. lay" because it is the appropriate past tense form of "lie" when referring to reclining on the bed.