How does plate tectonics as it relates to the formation of ocean basins help to explain the discrepancy in the age of the water in the ocean (collected over 4 billion years) and the maximum age of the much younger oceanic crust which forms the ocean floors

You have been tasked with sorting the rock samples shown into three categories, with two rocks in each category. what attribute would you use to sort these rocks? which rocks would be in each category? rocks: obsidian, coquina limestone, granite, soapstone, pumice, and gneiss.