4. You are a fixed-income manager of a portfolio that consists of many bonds. Your analyst has calculated the portfolio's overall duration and you are confident in the precision of that calculation. You can use that duration to accurately estimate your portfolio's: A) Gain in value when yields drop by 20 to 30 bps depending positioning in the yield curve B) Gain in value when yields drop by 400 bps across the entire curve C) Loss in value when yields rise by 20 bps across the entire curve D) Loss in value when yields rise by 400 to 500 bps depending positioning in the yield curve E) Both B and C