In order to have established an Archer MSA, a taxpayer must have been either one of the following - (1) an employee of a small employer that maintains a self-only or family HDHP for the taxpayer, or (2) a self-employed person who maintains a self-only or family HDHP. In this context, a "small employer" may be each EXCEPT which of the following?

a. A growing employer that had an average of 500 or fewer employees each year after 1996

b. A growing employer that madea contribution that was deductible as a Archer MSA for the last year the employer had 50 or fewer employees, but now has grown to 175 employees in the last 3 years

d. An employer that had an average of 50 or fewer employees during either of the last 2 calendar years