The British Prime Minister Is Called "First Among Equals" Because

The British prime minister is called "first among equals" because of which of the following?

A) He or she must represent a particular legislative district before gaining leadership in the political party.
B) He or she is never independent of the legislative body from which they were selected.
C) He or she must operate according to the party platform.
D) He or she is the leader of the political party.
E) He or she must represent a particular legislative district before gaining leadership in the party, is never independent of the legislative body from which he or she was selected, must operate according to the party platform, and is the leader of the party.