Which one is not a correct practice under the GAAP?

a.	ARB 43 noted that there are two separate types of intangibles: those having a term of existence limited by regulation and others and those having no such term of existence.
b.	Goodwill should be amortized as an expense over less than 40 years.
c.	Generally R&D is recorded as a current expense.
d.	all of the above are correct.