Final answer:
The answer should have three significant figures.
Step-by-step explanation:
In the given calculation (1.40) x (17.1), we need to determine the number of significant figures in the answer.
When multiplying or dividing numbers, the result should have the same number of significant figures as the number with the fewest significant figures.
In this case, both numbers have three significant figures. Therefore, the answer should have three significant figures.
So, the correct answer is 4) 3.