pdi question 297 discussion

Question 297

Universal Containers (UC) uses a custom object called Vendor. The Vendor custom object has a
master-detail relationship with the standard Account object.
Based on some internal discussions, the UC administrator tried to change the master-detail
relationship to a lookup relationship, but was not able to do so.
What is a possible reason that this change was not permitted?

• A. The Account object does not allow changing a field type for a custom field.
• B. The organization wide default for the Vendor object is Public Read/Write.
• C. The Account object has a roll-up summary field on the Vendor object.
• D. Some of the Vendor records have null for the Account field.