Answer:
C. 3.0 × 10⁸
Explanation:
A is invalid since using a negative exponent shows an incredibly small number, which the speed of light is not.
B is invalid because 299,792,458 rounds up, since 9, the digit after 2, is larger than 4.
From here, we count the number of digits from the smallest end of the number to the second largest, since in scientific notation, the decimal point is after the first digit.
2 9 9 , 7 9 2 , 4 5 8
8 7 6 5 4 3 2 1
Since there are 8 digits, the power will be 10⁸, so C. 3.0 × 10⁸ is the answer.