Final answer:
The result of the calculation 1.6×10¹⁹ would have 2 significant figures. So, the correct answer is A. 2.
Step-by-step explanation:
When multiplying or dividing numbers, the result should have the same number of significant figures as the least precise number being multiplied or divided. In the given calculation, we have a single number 1.6×10¹⁹, which has two significant figures. Therefore, the answer to the calculation would also have two significant figures. So, the correct answer is A. 2.