A 4 km optical link consists of multimode step index fiber with core refractive index of 1.3 and a relative refractive index difference of 1%. Find the delay difference between the slowest and fastest modes at the fiber output.

• A. 0.173 ‚âà√≠¬¨‚à´sec
• B. 0.152 ‚âà√≠¬¨‚à´sec
• C. 0.96 ‚âà√≠¬¨‚à´sec
• D. 0.121 ‚âà√≠¬¨‚à´sec