What is true about a master-detail relationship? (Choose 2 options)

Answer options:

A. Deleting a parent record will delete all child records
B.The master object cannot be a standard object
C.By default, the child record cannot be reparented.
D. The child record inherits the sharing settings from the parent

Correct Answer: A and C 
You can’t delete a custom object if it is on the master side of a master-detail relationship. And if you delete a custom object that is on the detail side of a master-detail relationship, the relationship is converted to a lookup relationship. 
Deleting a detail record moves it to the Recycle Bin and leaves the master record intact; deleting a master record also deletes related detail and subdetail records. Undeleting a detail record restores it, and undeleting a master record also undeletes related detail and subdetail records. However, if you delete a detail record and later, separately, delete its master record, you cannot undelete the detail record, as it no longer has a master record to relate to. 
By default, records can’t be reparented in master-detail relationships. Administrators can, however, allow child records in master-detail relationships on custom objects to be reparented to different parent records by selecting the <samp>Allow reparenting</samp> option in the master-detail relationship definition. 
Other options are incorrect because a master object cannot be a standard object and the detail record also inherits the sharing rule from master records, but the child record cannot inherit the sharing settings from the parent. 
Reference: 

https://help.salesforce.com/articleView?id=relationships_considerations.htm&type=5