The correct answer is:
B.11 mm²
Explanation:
When dealing with significant digits in our answer, we want our product to have the same number of significant digits as our least precise number (the one with the fewest significant digits).
One of our factors, 2.2, has 1 significant digit. The other, however, can be written as 5; this means that it has the fewest significant digits, so we want to write our product, 11, as 11 with no decimal.
