Gym-Fantastic, a local gymnastics studio, has a SEP for its 5 full-time employees. This year, as in the previous 5 years, the business has made a substantial profit. Gym-Fantastic

a) must make contributions at least as often as comparable defined contribution plans

b) must make a contribution to the SEP every year that there is profit

c) can choose to make a contribution or not, but must be sure to make "substantial and recurring" contributions to the SEP

d) must make a contribution to the SEP every year, whether or not there is profit

e) can omit any year's contribution to the SEP without concern of disqualification of plan or loss of tax advantages