Question

Change .00025 to scientific notation

Answer 1

After you realize that
  0.00025 = 2.5·10^-4
    = 250·10^-6 or 250 μ
    = 250,000·10^-9 or 250,000 n
then it becomes a matter of semantics. Both A and D are correct representations, so choice B is incorrect.

Choice C present a dilemma. If you say it is correct, then there are 3 correct choices (A, C, D), not two, so C is incorrect.

If you say it is incorrect, then there are two correct answers (A, D), making choice C correct.

I'd probably choose C and try to avoid the argument with my teacher.