Final answer:
The institution must make the written notice available no later than three business days after receiving notice from the FFIEC.
Step-by-step explanation:
The correct answer is D. Three business days.
According to the question, the institution must make available to the public, upon request, a written notice that clearly states its disclosure statement may be obtained on the CFPB's website. The deadline for making this notice available is no later than three business days after receiving notice from the FFIEC.
It is important for the institution to provide timely access to the disclosure statement to ensure transparency and compliance with consumer protection laws.