1099-R distribution code 4

my wife receives a 1099-R with distribtuion code 4 from state"A".  Her previous husband passed away as a police officcer in state "A" and she gets a monthly amount sent to her, summarized in this 1099-R.  We live in state "B".  i am presuming this is not taxable in "A" (there is no state withholding, only federal) but how do i find out if it is taxable on the state "B" return we file?  Thank you.