As far as I know, they can't ask you for that. All they need to know (and should know) is that you have authorization to work in the United States. No person can be hired on the sole basis of their legal status.
For example, a citizen, permanent resident and alien allowed to work stand on the same ground. As long as they call can provide work authorization.
__________________
| Applied with: Lawyer in CA | EWI | Packet sent: 10/11/2012 to Phoenix, AZ Lockbox | Delivered: 10/12/2012 | Signed off by: E. Arndt | G1145 Notification: 10/17/2012 routed to California| I-797C: 10/20/2012 | Biometrics: R'cvd 10/19/2012 for 11/05/2012 | Walk-In: 10/22/2012 | Approved: 5/3/2013 | EAD Sent: 5/7/2013 | EAD Rcv'd: 5/10/13 | SSN card: Issued 1990 |CA DL: Issued 2005