The correct option is **B. 123.4500**. ### Detailed Explanation **Understanding Significant Figures:** Significant figures (or significant digits) are the digits in a number that contribute to its precision. This includes all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion. Here’s how to determine the number of significant figures in each option: 1. **Option A: 0.00456** - The leading zeros (0.00) are not significant; they only serve to position the decimal point. - The significant figures here are 4, 5, and 6. - **Total significant figures: 3.** 2. **Option B: 123.4500** - All digits are significant here. The digits 1, 2, 3, 4, 5 are non-zero and significant, and the trailing zeros after the decimal point (00) are also significant because they indicate precision. - **Total significant figures: 6.** 3. **Option C: 1002.0** - The digits 1, 0, 0, 2 are significant, and the trailing zero after the decimal point (0) is also significant. - **Total significant figures: 5.** 4. **Option D: 0.0200** - The leading zeros (0.0) are not significant. The significant figures are 2 and the two trailing zeros (00) after the 2, which indicate precision. - **Total significant figures: 3.** ### Why the Other Options are Incorrect or Weaker - **Option A (0.00456)** has only 3 significant figures, which is fewer than the 6 in Option B. - **Option C (1002.0)** has 5 significant figures, which is also fewer than the 6 in Option B. - **Option D (0.0200)** has 3 significant figures, which is again fewer than the 6 in Option B. ### Summary of Key Points - Significant figures include all non-zero digits, zeros between significant digits, and trailing zeros in the decimal portion. - **Option B (123.4500)** has the highest number of significant figures (6), making it the correct choice. - Leading zeros do not count as significant figures, while trailing zeros in a decimal context do. ### Revision Summary - Significant figures are crucial for indicating precision in measurements. - Leading zeros are not significant; trailing zeros in a decimal are significant. - The number of significant figures varies among options; always count carefully. - **Correct answer: B. 123.4500 (6 significant figures).**