For each situation listed below, select the appropriate inherent risk factor that is demonstrated. Each inherent risk factor can be used once, more than once, or not at all.

a$.$ A client is estimating an amount that may be owed pending the outcome of a lawsuit that may take several years to resolve.

b$.$ Management hires a specialist to assist with determining the value of an inventory of precious gemstones.

c$.$ Due to a global pandemic, the airline industry is experiencing unprecedented disruption of normal business operations.

d$.$ Management is estimating the fair value for a derivative financial instrument that is not traded on a public market.

A client must derive a future interest rate by using interpolation techniques from forward interest rates.