What Use May a Court of One State Make of an Earlier

What use may a court of one state make of an earlier state court decision made in another state?

A) If the earlier decision in the other state is relevant, it must be followed even though it is from another state because all of the states are part of one legal system.
B) When deciding the case, the court deciding the case cannot take the decisions of other states into account.
C) Earlier court decisions are equally relevant as precedent whether they were made in the same state or in a different state.
D) The court of the state deciding a case can look to earlier court decisions in other states for guidance in deciding the case at hand, but is not required to follow them.
E) The decision is legally binding.