FM and PC were cohabiting with each other without the benefit of marriage. Later FM donated a parcel of land to PC. After FM's death his sister sought for the nullification of the donation, citing the Civil Code provision which states that: "Every donation between spouses during marriage shall be void." PC, through counsel, argue that such provision is inapplicable to her case because it was made at the time when they were not married and were simply living together as husband and wife. Is such argument justifiable