Sea level is the level of the sea's surface in regard to the height of a geographical feature such as hills or mountains. An example is when they state something is '100 feet above sea level' meaning that the feature's height is 100 feet above the level of the sea's surface.
From an archived question I looked up for you, I believe it should be water-table aquifers. By the way, if you look in the link above, replace the 4449929 with 482974 to see the answer to it!
I'd say A and B because the closes you are to the epicenter the more damage there is and also how many people are within the radius