Which of the Following Constitutes a Positive Feedback Loop for Global

Which of the following constitutes a positive feedback loop for global warming?

A) Greenhouse gases (ghgs) trap or block infrared radiation from the earth, which warms the
Planet, so that more water vapor accumulates in the atmosphere.
B) Ghgs trap heat from the sun and re-direct it towards the earth.
C) Ghgs trap heat from the earth, warm up the planet, which then results in an increase of
Carbon dioxide in the atmosphere.
D) All of these constitute a feedback loop for global warming.
E) None of these constitute a feedback loop for global warming.