When the United States' Legal System Is Described as a "Dual

When the United States' legal system is described as a "dual court system," it means that

A) there are two types of courts: civil and criminal.
B) there are two systems of courts: state and federal.
C) criminal defendants may always appeal their decision at least twice.
D) cases are always heard by at least two judges.
E) those accused of a crime may not be convicted unless at least two juries agree on a verdict.