Two coaxial solenoids 1 and 2 of the same length are set so that on...

Two coaxial solenoids 1 and 2 of the same length are set so that one is inside the other. The number of turns per unit length are \( n_{1} \) and \( n_{2} \). The current \( i_{1} \) and \( i_{2} \) are flowing in opposite directions. The magnetic field inside the inner coil is zero. This is possible when
I. \( i_{1} \neq i_{2} \) and \( n_{1}=n_{2} \)
- II. \( i_{1}=i_{2} \) and \( n_{1} \neq n_{2} \)
HII. \( i_{1}=i_{2} \) and \( n_{1}=n_{2} \)
[V. \( i_{1} n_{1}=i_{2} n_{2} \)
Which of the following statement(s) is/are correct?
(a) I and II
(b) II and III
(c) III and IV
(d) I and IV
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