The weight of the empty dump truck is 2.8 x 10^5 pounds. If 15,300 pounds of trash is added to it, the total weight would be 2.8 x 10^5 + 1.53 x 10^4 pounds.
To add these two numbers in scientific notation, we need to make the exponents the same.
To do this, we can rewrite 1.53 x 10^4 as 1.53 x 10^4 x 10^1, which is equal to 1.53 x 10^5.
Now we can add the two numbers: 2.8 x 10^5 + 1.53 x 10^5 = 4.33 x 10^5.
Therefore, the correct answer is option 2. 4.33 x 10^5 pounds.