Final answer:
The instance of entity type cannot be tracked because another instance is unrelated.
Step-by-step explanation:
The subject of this question is Computers and Technology and the grade level is High School.
The correct answer to the question is A) instance is unrelated. When an instance of an entity type cannot be tracked, it means that it is not related to another instance. This may happen when the two instances are not connected or have no correlation.
For example, let's say we have two entities, A and B. If the instance of entity type A cannot be tracked, it means there is no connection or relationship between A and any other entity.