Final answer:
Students under the age of 18 can take the Class E Knowledge Exam online at 15 years old.
Step-by-step explanation:
The correct answer is d) 15 years.
According to the Florida Department of Highway Safety and Motor Vehicles, a student under the age of 18 can take the Class E Knowledge Exam online at the age of 15. This exam is required for teens to obtain a learner's license in the state of Florida.
Online exams provide a convenient option for teenagers to study and prepare for their driving tests at their own pace.