Consider Robert Trivers' Parent-Offspring Conflict Model

Consider Robert Trivers' parent-offspring conflict model. How do you expect the zone of conflict between parent and offspring to differ when the future offspring is a half instead of a full sibling?

A) The zone of conflict will become wider.
B) The zone of conflict will become narrower.
C) The zone of conflict will remain of the same width but shift toward higher parental investment.
D) The zone of conflict will become wider and shift toward higher parental investment.