Final answer:
An employee undergoing classroom training and working under supervision is normally called an apprentice, as they are in a structured program that includes practical skills and theory.
Step-by-step explanation:
An employee who spends time in the classroom and works under close supervision in training is typically known as an intern or an apprentice. However, the question specifies that the individual is in training, which suggests that the person is learning through a structured program that combines theory with practical skills. This description aligns more closely with an apprentice than an intern. Apprenticeships are often associated with trades and include both classroom instruction and on-the-job training under the supervision of a skilled worker. Internships can also involve close supervision and mentorship, but they are typically not as structured around classroom learning as apprenticeships are.