In the context of the chain of command in an organization, which of the following is a difference between line authority and staff authority?

a$.$ Line authority is the right of top managers to advise first$-$line managers, whereas staff authority is the right of first$-$line managers to command middle managers.

b$.$ Line authority is the right to advise people who are not subordinates, whereas staff authority is the right to command people who are not subordinates.

C$.$ Line authority is the right to command immediate subordinates, whereas staff authority is the right to advise but not command people who are not subordinates.

d$.$ Line authority is the right to advise but not command immediate subordinates, whereas staff authority is the right to command immediate subordinates.