What is (1.5×104)+(5.0×103)(1.5 \times 10^4) + (5.0 \times 10^3)(1.5×104)+(5.0×103)?
2.0×1042.0 \times 10^42.0×104
6.5×1076.5 \times 10^76.5×107
6.5×1036.5 \times 10^36.5×103
2.0×1072.0 \times 10^72.0×107