Which of the Following Is a Defining Characteristic of VERs

Which of the following is a defining characteristic of VERs?

A) International regulatory bodies set export/import limits.
B) The importing country can levy heavier import tariffs to override the VERs.
C) The exporting country sets the limits on the quantity it will export.
D) It is a mandatory tax imposed by a government on goods entering at its borders.
E) It is an absolute restriction against the importation of certain goods.