Task: Property Constraint Reasoning (ontology: Business_Finance/Financial_Industry_Business_Ontology)

The property 'has monitoring period' applies to instances of 'barrier option', and 'double barrier option' is a subclass of 'barrier option'. Which class can appear as the value of 'has monitoring period' for instances of 'double barrier option'?

A. date period
B. observed best value
C. floating lookback strike expression
D. Asian option classifier

Answer: date period