D. Near the centre of a large plate
(not 100% sure but i think it is correct)
The correct answer is - glacial erosion and sea level rise.
The glaciers make U shaped valleys as they move downwards. When they come to the sea they melt (if the sea is not frozen as well). So once the whole glacier starts to melt it leaves behind a U shaped valley, and when the last ice age finished they did melt, but also the sea level rose, so the sea filled the U shaped valleys left by the glaciers, thus the fjords formed.
A. perishable items spoil quickly
B nitrogen were trapped in rocks during extensive volcanic activity
