Can someone please tell whether Contracts are Risk Mitigate or Transfer response strategy? Which is best option when both are given? Is it dependent upon specific type of contracts?

In some places, I see its Mitigate strategy.

But in Pmbok (Pg 303), Contracts can be used to transfer liability of some risk to seller. Cost-plus contracts may transfer cost risk to the buyer. And FP contracts may transfer cost risk to the seller.

Thanks.