What Did a Study of Jet Contrails Undertaken After the Grounding

Multiple Choice

What did a study of jet contrails undertaken after the grounding of commercial flights after the September 11,2001 terrorist attacks find?

A) The study found that contrails have a very limited effect on Earth's energy budget.
B) The study found that contrails reduce diurnal temperature ranges in regions with a high density aircraft.
C) The study found that contrails contribute more to cloud-albedo forcing than cloud-greenhouse forcing.
D) The study found that contrails are difficult to distinguish from natural cirrus clouds.