Task: Inferred Class Relation Reasoning (ontology: Business_Finance/Financial_Industry_Business_Ontology)

After reasoning, which of the following classes is one valid superclass of 'ForeignExchangeRateObservable'?

A. interest rate derivative instrument
B. forward rate agreement
C. rate-based derivative instrument
D. EconomicRateObservable

Answer: EconomicRateObservable