What is the time window to pay the issue fee after receiving a notice of allowance?

The correct answer is the three-month time window to pay the issue fee after receiving a notice of allowance is established in the rules of the United States Patent and Trademark Office (USPTO). When an applicant receives a notice of allowance, they are granted a period of three months to pay the required issue fee. This timeframe is crucial, as the payment of the issue fee within this period is necessary for the application to advance toward granting a patent.

The rules specify that if the issue fee is not paid within this three-month window, the application may be considered abandoned, and the applicant may lose the opportunity to obtain the patent. Thus, adhering to the three-month deadline is an essential responsibility for applicants following the notice of allowance.