for the purpose of electing to roll over gain from the sale of qualified small business stock, all of the following requirements must be met except?

a. another qualified small business stock must be acquired during a 60 day period following the date of the sale

b. only non corporate taxpayers may make such an election

c. the amount of gain that may be deferred is limited to $50,000 a year

d. the qualified small business stock must have been held for more than six months