Final answer:
The range of the function is all real numbers less than negative infinity.
Step-by-step explanation:
The range of a function refers to the set of all possible output values that the function can produce. In this case, the function is not specified. If a function is described as having a range of "all real numbers less than negative infinity," it means that the function can output any real number, but it cannot output positive infinity. Therefore, the correct answer is A. All real numbers less than negative infinity.