Which of the following explore(s) the question,"How do I know that the test,scale,instrument,and so on,I use works every time I use it?"

A) reliability
B) validity
C) both reliability and validity
D) neither reliability nor validity

Reliability examines consistency and stability in measurement, which means it assesses whether the test or instrument produces consistent results every time it is used. Therefore, it directly relates to the question of how to know if the tool works every time. Validity, on the other hand, focuses on whether the measuring tool measures what it is intended to measure, which is not necessarily related to precision and replicability.