Answer:
Assuming that the 14th is a business day so that it can be considered the banking day on which the deposit was received, the 15th will be the first business day following the banking day of deposit.
If funds are due to be available on the 17th, they have to be available for cash withdrawal no later than 9:00 am on the 17th, assuming that your offices or ATMs are available at the same time or earlier. Whether the availability is memo posted or hard posted is irrelevant.