Getting an error that says:
Challenge Not yet complete... here'w what's wrong: could not find an opportunity list view named 'High Probability Opportunities'.

But I'm looking at the list view. I also don't see 'Proposal/Price Quote' and 'Negotiation/Review' as options to filter by. Are these items that I need to create?

Objective: The object you created for the previous challenge is pretty handy. Imagine how much more useful it would be if brokers could specify which client made an offer and which property the client wants to buy. Add two relationships to the Offer object so brokers can capture this data in Salesforce. Create a Master-Detail relationship with the Property object and a Lookup relationship with the Contact object.
On the Offer object, add a Master-Detail relationship to the Property object named Property

Error Message Received: You cannot create a new Master-Detail relationship on an existing custom object if records already exist. You must first create a Lookup relationship, populate the lookup field with data in all records, and then change the relationship type to Master-Detail.