Answer:
A. Volcanic activity
Step-by-step explanation:
Albedo is the amount of total radiation that is reflected from the earth surface.
When volcanic eruptions occur, trapped gases that drives explosions are released into the atmosphere. Some of these gases are greenhouse gases.
Greenhouse gases helps to trap heat on the earth surface and warm it.
As solar radiation impinges on the earth, the increasing emission of these gases helps trap the radiation and thus the earth's albedo would decrease.