The British Party System Is Often Called a Two-And-A-Half Party

The British party system is often called a two-and-a-half party system because:

A) the MPs in Parliament are notoriously hard to control, and their independence counts as a sort of third party.
B) the Labour Party has two unofficial wings that operate with different policy objectives.
C) the House of Lords is part of government but is not popularly elected.
D) the Scottish National Party holds only a regional sway instead of a national one.
E) the Liberal Democratic Party trails far behind the Conservative and Labour parties in electoral strength.