GKFix MCQ Question

What is the expression for magnetic flux through the smaller coil in the concentric setup?

• A. Φ₁ = µ₀I₂πr₂²/(2r₁)
• B. Φ₁ = (µ₀I₂πr₁²)/(2r₂)
• C. Φ₁ = µ₀I₂r₁²/(2r₂)
• D. Φ₁ = µ₀I₂πr₁r₂/2