The given question asks to round off the division of 3125 by 8 to 3 significant figures. To round off to 3 significant figures, we start from the leftmost non-zero digit and count three digits from there. In this case, the leftmost non-zero digit is 3, and counting three digits from there gives us 391. Therefore, the correct answer is 3125 divided by 8 equals 391, rounded to 3 significant figures.