F and I are not correct since F creates a negative number and I creates a large number.
You have to see how many digits you have to move the decimal point to get from the current number to 5.89 (in scientific notation, <em>there is exactly one digit before the decimal point</em>, regardless of rounding), which you've done, and should've gotten 7 points. So your answer would be H. 5.89 × 10⁻⁷.