You need to read the instructions that @Mike9241linked for form 8832; especially the section on late election relief.
Complete the form / election and make sure you send the election / form certified mail return receipt requested.
You should not file any return until you receive a response from the IRS. That response will indicate the entity type, which will then dictate which tax return to file.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
