Which of the following types of unemployment is most likely to be associated with an economy in which many workers have been made obsolete by changing technology（）

A. Cyclical.

B. Frictional.

C. Structural.

根据营业税法律制度的有关规定，纳税人因财务会计核算办法改变将已缴纳过营业税的预收性质的价款逐期转为营业收入时，不得从当期营业额中减除。（）