One Difference Between a Policy of Direct Spending by the Government

One difference between a policy of direct spending by the government on research and development and an alternative policy of tax incentives to encourage private spending on R&D is ________.

A) the former improves the productivity of R&D,while the latter raises its level
B) the former requires a decrease in national saving,while the latter causes an increase
C) the former raises the level of R&D spending,while the latter also improves its productivity
D) the former requires an increase in national saving,while the latter causes a decrease