Answer:
[tex]\large\boxed{C.\ 3.59\times10^5}[/tex]
Step-by-step explanation:
[tex]\text{The scientific notation:}\\\\a\cdot10^k,\ \text{where}\ 1\leq a<10\ \text{and}\ k\in\mathbb{Z}.\\--------------------\\\\\text{We have}\\\\26.5\times10^4+9.4\times10^4=(26.5+9.4)\times10^4=35.9\times10^4\\\\=3.59\times10\times10^4=3.59\times10^5[/tex]