Opton free bonds, effective duration

B is correct in the following. I thought effective duration is for only bonds without embedded options. Any comments? ------------------------------------------ Interest rate sensitivity for bonds with embedded options is most accurately measured by: A. Convexity. B. Effective duration. C. Modified duration. D. Macaulay duration.

Effective duration is for option free or embedded bonds. Macaulay and modified duration are only for option free bonds