You Plant a Seed in a Pot Containing Soil,and Then

You plant a seed in a pot containing soil,and then add water and place the pot under a light.In the first week,before the seedling even emerged from the soil,carbon dioxide levels increased in the closed chamber.The developing plant was using which of the following as a source of energy during this first week?

A) light
B) starch from the seed
C) water from the soil
D) sugars from the soil
E) nutrients from the soil