A Friend Asks You About What Has Caused Global Warming

A friend asks you about what has caused global warming.You explain

A) as carbon dioxide and other gases have increased in the atmosphere,the global temperature has increased due to trapped solar radiation.
B) as carbon dioxide and other gases have increased in the atmosphere,the global temperature has increased due to ozone depletion.
C) as carbon dioxide and other gases have increased in the atmosphere,the global temperature has increased due to acid precipitation changing the pH of the atmosphere.
D) that there really is no evidence for global warming and these are mere scare tactics being used by environmentalists to reduce oil consumption.