The Degree of "Flatness" of the Universe,which Determines Whether We

The degree of "flatness" of the universe,which determines whether we live in an open or a closed universe,has been determined recently by measuring the

A) average density of matter compared to the average density of radiation energy.
B) typical size of the "hot spots" in the structure of the cosmic microwave background.
C) hemispheric asymmetry in the temperature of the cosmic microwave background radiation.
D) extent of the bending of light from distant galaxies,the so-called "lensing."