When all else fails, look up the instructions https://www.irs.gov/pub/irs-pdf/i109495c.pdf See page 12 

2A. Employee not employed during the month. Enter code 2A if the employee was not employed on any day of the calendar month. Do not use code 2A for a month if the individual was an employee of the ALE Member on any day of the calendar month. Do not use code 2A for the month during which an employee terminates employment with the ALE Member. 

2B. Employee not a full-time employee. Enter code 2B if the employee is not a full-time employee for the month and did not enroll in minimum essential coverage, if offered for the month. Enter code 2B also if the employee is a full-time employee for the month and whose offer of coverage (or coverage if the employee was enrolled) ended before the last day of the month solely because the employee terminated employment during the month (so that the offer of coverage or coverage would have continued if the employee had not terminated employment during the month)