Answer: The sentence that is an example of a concrete statement is B. "I have four years of experience using both the Falcon X and LionCoat software systems".
Explanation: A concrete sentence is a sentence that provides information that is clear and certain. Moreover, concrete sentences are based on evidence; therefore, examples are generally included in them. The only sentence among the options that can be described as concrete is B. ("I have four years of experience using both the Falcon X and LionCoat software systems") since it is a statement that refers to an actual experience, that is specific (especially when the word "four" is used to make reference to the years of experience) and that gives examples ("the Falcon X and LionCoat").
