Which Is Not Correct in the Following Statements

Which is not correct in the following statements:

A) Collation is a mere mathematical operation by the addition of the value of donations made by the testator to the value of the hereditary estate.
B) Collation is the return to the hereditary estate of property disposed of by gratuitous title by the testator during his lifetime.
C) One of the purposes of collation is to secure equality among the compulsory heirs in so far as it is possible and to determine the free portion after finding the legitime so that inofficious donations may be reduce
D) (6 Manresa 406)