Final answer:
The term for a serious violation of God's law resulting in loss of grace is C) Mortal sin. It is the most severe sin and requires three conditions to be met: grave matter, knowledge of the sin, and consent.
Step-by-step explanation:
The term that refers to a serious violation of God's law of love resulting in the loss of sanctifying grace is C) Mortal sin. Mortal sin is considered the most severe form of sin in Christian theology. It not only damages one's relationship with God but also represents a willful turning away from God's laws. To be considered a mortal sin, three conditions must be met: grave matter, full knowledge of the sinful action, and deliberate consent to it. Mortal sins must be confessed and absolved through the sacrament of Penance. If not repented, it is believed that mortal sin deprives the soul of eternal life with God.