Answer:
The correct answer is 3.
Explanation:
When you are not using a decimal after the whole number the extra zeros are not required. The number can still be recognized without the zeros.
Example: 832,000 km only has three significant numbers, as it can still be recognized without the zeros.
However, 832,000.0 km has seven significant numbers, as it cannot be recognized without the decimal. The number after the decimal says that the number continues into the tenths place, which is required when writing statistics.
Hope this helps!