I inherited an IRA from my mother and received a 1099R, turbo tax is asking how much was a Required Minimum Distribution. What do I need to enter?

[MarilynG1]

If your mother was required to take a Minimum Distribution, the plan administrator was responsible for making sure that was done properly.

You can choose 'all of the distribution was RMD' in TurboTax, when entering your 1099-R.

Here's more info on Inherited Pension Plans. 

[dmertz]

TurboTax is really asking how much is ineligible for rollover.  Because all of such a distribution is ineligible for rollover simply say that all of it is RMD.  (It actually doesn't matter what answer you give to this questions that TurboTax needlessly asks under the circumstances).