Final answer:
Multiplying -1 by itself 12 times results in 1 because the pairs of negative numbers each give a positive product and 12 is an even number.
Step-by-step explanation:
The multiplication of negative numbers follows specific rules. When multiplying an even number of negative numbers together, the result is positive. This is because the product of two negative numbers is always positive, and when pairing each of the negatives in the multiplication, all negative pairs will result in a positive product.
In the given problem, we are multiplying -1 by itself twelve times. Since twelve is an even number, thus the pairs of negatives will result in a positive number 1. Hence, (-1) × (-1) × ... × (-1) repeated 12 times will be equal to 1, which is option A.