Concept:A strong argument is one that is directly relevant, factually sound, and important to the given statement.
Explanation:Argument I states that mobile phones distract students from studies and encourage cheating in exams.
This directly affects school discipline and academic performance, so it is a strong reason to support a ban.
Argument II states that mobile phones are needed for communication and emergencies.
Student safety and the ability to reach parents are also valid and important concerns.
These two arguments are contradictory in direction, but contradiction does not reduce their individual strength.
An argument supporting the ban and an argument opposing the ban can both be strong at the same time.
Hence, both arguments are strong and should be considered together.
Answer:Option D — Both I and II are strong.