Which of the following is not subject to the "Nanny Tax"?

The "Nanny Tax" refers to the IRS taxes that are applicable to household workers such as nannies, housekeepers, and caregivers, under certain conditions. This tax is specifically focused on workers who are hired to work in a private household.

The babysitter who works with multiple families is not subject to the "Nanny Tax" because they are considered self-employed if they have multiple clients and set their own hours. This classification means that they are not classified as a household employee. Under IRS guidelines, a household employee is someone who is controlled by the employer in terms of how and when the work is done, as opposed to someone who operates independently and markets their services to a variety of clients.

On the other hand, a part-time yard worker, an hourly housekeeper, and a once-per-week private nurse would likely be classified as household employees since they perform work directly for a single household under the control of that household's owner. Therefore, their wages would be subject to the "Nanny Tax" if they meet the earnings threshold established by the IRS.