A pure educational voucher system will necessarily lead to which of the following, assuming that higher levels of spending lead to higher levels of educational quality?

a - Each family with school-aged children receives a fixed amount that can be spent at any public or private school.

b - Each family with school-aged children would reduce private spending on education.

c - There is crowding-out of private spending on education.

d - Only low-income families receive assistance with the cost of private education.