The tax laws allow taxpayers to use which of the following methods of accounting for research and experimental costs paid or incurred in connection with a trade or business?

1)	Deduct the expenses in the year in which they are paid or incurred.

2)	Capitalize the expenses and amortize them ratably over a period of at least 60 months beginning in the month that the benefits are first realized.

3)	Capitalize the expenses, but do not amortize them.

4)	All of the above.