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

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

A. cliquet option
B. lookback strike terms
C. observed best value
D. date period

Answer: date period