To subtract 4.66 x 10^-5 from 7.34 x 10^-7, we need to make sure the exponents are the same.
First, let's convert 4.66 x 10^-5 to scientific notation with the same exponent as 7.34 x 10^-7:
4.66 x 10^-5 = 0.0000466 x 10^-5 = 4.66 x 10^-7
Now, we can subtract the two numbers:
7.34 x 10^-7 - 4.66 x 10^-7 = (7.34 - 4.66) x 10^-7 = 2.68 x 10^-7
Therefore, the correct answer is C) 2.68 x 10^-7.