Final answer:
The statement that is true in this scenario is d. Unclear as it depends on the value of the current house relative to the value of the inherited house.
Step-by-step explanation:
It is unclear whether it was a good decision for your parents to move into your grandparents' house and sell your current house without knowing the respective values of the two properties.
If the current house is more valuable, then it may not be a good decision since they could potentially get more money by selling it. On the other hand, if the inherited house is more valuable or has sentimental value, then it could be a good decision for them.