What Is the "Cosmological Constant

Multiple Choice

What is the "cosmological constant?"

A) The universe has existed forever and on the average (over billions of cubic light years) does not change.
B) This is the ratio between "dark energy" and "dark matter."
C) This is a quantity also referred to as "quintessence."
D) This is a self-admitted blunder in his theory of general relativity by Einstein,that might not be a blunder after all.