Which is the best estimate for the product of 123.519 × 311,982.21? a. 372,000,000 b. 37,200,000 c. 3,720,000 d. 372,000

B, these numbers are all the same, so in the end it's whichever Digit is the closes, but each gap is that changing by entire Tens of thousands.
The sum of those numbers has 8 digits, the only answer with 8 digits--

The answer is