A flexible wire loop in the shape of a circle has radius that grown linearly with time. There is a magnetic field perpendicular to the plane of the loop that has a magnitude inversely proportional to the distance from the center of the loop, \[B(r)\propto \frac{1}{r}\].How does the emf E vary with time?

• A. \[E\propto {{t}^{2}}\]  
• B. \[E\propto t\]
• C. \[E\propto \sqrt{t}\]        
• D. E is constant