Complete Question
The entire question is displayed in the first uploaded image
Answer:
The right choice is option 3
Explanation:
The question informs us that
The diameter of solenoid 1 is 
The length of solenoid 1 is 
The number of turns of solenoid is 
The diameter of solenoid 2 is 
The length of solenoid 2 is 
The number of turns of solenoid 2 is 
Typically, the magnetic field in a solenoid can be expressed mathematically as

According to this formula we find that


Here C denotes constant
=> 
=> 
=> 
=> 
=> 
=> 