Final answer:
The product of any integer and -1 will be the negative of that integer, and therefore, the result varies depending on the integer.
Step-by-step explanation:
The product of any integer and -1 will always be the negative of that integer. This is because when a positive number is multiplied by -1, the result is negative, and when a negative number is multiplied by -1, the result is positive. According to the rules of multiplication of integers, the product of two numbers with opposite signs will have a negative sign. Therefore, the correct answer to the question is D) The result varies depending on the integer.