Organization wide default (OWD) is the first check used for determining access to records a user does not own.
'Status' is a picklist of the Account object having value 'Open' or 'Closed'. It is possible to create a sharing rule to share only those Accounts whose 'Status' is 'Open'.
Which of these standard objects cannot be shared? Account, Opportunity, Lead, Case, Product, Campaign, Contract, Contact
'View All' has been checked at the profile level for a custom object Position but 'Modify All' has not been checked. OWD is read/write of the Position object. Any user can delete Position records owned by other users.
Roll up summary field and Cross object formula field can be created only for master detail relationship.