The amounts of plastic waste generated in a region during two years were 32,400,000 tons and 20,300,000 tons. what was the total plastic waste generated over these two years in the region, expressed in scientific notation? 
a.52.7 ⋅ 1014 tons 
b.52.7 ⋅ 107 tons 
c.5.27 ⋅ 107 tons 
d.5.27 ⋅ 1014 tons