Final answer:
The correct code for Wardrop's disease is 681.9.
Step-by-step explanation:
The correct code for Wardrop's disease is 681.9.
In the given information, the codes are listed alphabetically, and the code for Wardrop's disease falls under the section starting with 'W'. By careful examination of the options, it can be identified that only option 681.9 belongs to this section.
Therefore, the correct answer is 681.9.