Pension taxable in PA for state tax filing 1099-R Box 7 code

We are trying to determine the correct drop down selection for the "State Code Type" in determining the retirement distribution.
On my wife's 1099R, box 7 has a "2" which, on the back of the 1099R states 'early distribution, exception applies (under age 59 1/2)'. What "exceptions" apply in this case?
Let me know if you need additional information.
Thanks!