Answer:
The correct answer is A. He could design and execute a study that measures short-term memory function following different amounts of sleep.
Step-by-step explanation:
The empirical approach can also be known as the scientific method which consist on relying on experimentation and observation in order to prove or disprove previously stablished hypothesis.
The empirical approach relies on experience, on observation of interaction between variables and the analisis of said interactions.
In this particular case, the only optional answer that shows an empirical approach is answer a. He could design and execute a study that measures short-term memory function following different amounts of sleep, because it measures concrete variables, short term memory and amounts of sleep.
In conclusion, the correct answer is A.