Final answer:
To write 63,120,000 in scientific notation, move the decimal point seven places to the left, resulting in 6.312 × 10^7.
Step-by-step explanation:
To write 63,120,000 in scientific notation, we need to move the decimal point seven places to the left, since there are seven zeros at the end of the number.
Therefore, the answer is A) 6.312 × 10^7.