Correct Answer: A

Rationale: The correct subtraction is 12.02 - 9.99 = 2.03. Therefore, the correct answer is A. Choice B, 2.21, is incorrect as it does not result from the given subtraction. Choice C, 3.17, is also incorrect. Choice D, 7.97, is incorrect as well. Thus, A is the only correct answer.

Correct Answer: C

Rationale: Rationale: The correct answer is obtained by applying the formula for the circumference of a circle, which is \(C = \pi \times d\), where \(d\) is the diameter of the circle. By substituting the given diameter of 40cm into the formula and performing the calculation, we find that the circumference of the pizza is 125.6cm.

Correct Answer: C

Rationale: In this scenario, to find the total amount of medication administered in 3 hours, we first calculate the total drops administered by multiplying the drops per minute by the total minutes. This gives us 40 drops/minute * 180 minutes = 7200 drops. Then, we convert the drops to milligrams by multiplying the total drops by the amount of medication in each drop, which is 1mg. Therefore, 7200 drops * 1mg/drop = 7200mg. The correct answer is 7,200mg. Choice A is incorrect as it miscalculates the total amount. Choice B is incorrect as it doubles the correct answer. Choice D is incorrect as it quadruples the correct answer.

Correct Answer: C

Rationale: 1 kilometer equals 1,000 meters. Therefore, 2 kilometers equals 2,000 meters. Choice A, 100 meters, is incorrect as it represents only 1/10th of a kilometer. Choice B, 200 meters, is incorrect as it represents only 1/5th of a kilometer. Choice D, 3000 meters, is incorrect as it miscalculates the conversion from kilometers to meters.

Correct Answer: C

Rationale: To find the total surface area of the rectangular box, calculate the area of each side and sum them up. The areas of the sides are: 2(40x30) + 2(40x25) + 2(30x25) = 2400 + 2000 + 1500 = 5900 sq cm. Convert this to square meters by dividing by 10,000: 5900/10,000 = 0.59 sq m. Since one sheet covers 0.5 sq m, you would need 2 sheets to cover the box fully, which equals 1 sq m. Therefore, the correct answer is 1.2 sq m. Choice A (0.3 sq m) is too small for the dimensions provided. Choice B (0.6 sq m) is incorrect as it doesn't match the calculated surface area. Choice D (1.8 sq m) is too high for the surface area of the box.