First off, apologize if this question may be misplaced.
Situation:
Wife is on a conditional green card that expired a year ago. I am a US Citizen. Filed I-751 and got the 48 month extension. Case is currently just pending and no RFEs.
Wife will hit 3 years lawful permanent resident of April this year (starting from date of green card issuance).
Question:
Can she file for N400 while I-751 is pending? If so, how would that work?