The correct answer is A because modified duration estimates the percentage price change for a bond given a change in its yield-to-maturity. A modified duration of 2.4 implies a 2.4% price change for a 100 basis points change in yield. For a 50 basis points decrease in yields, the bond's price change is calculated as: (2.4)(0.0050)($912,575) = $10,951, which rounds to $11,000.

• B is incorrect as it uses an erroneous calculation: (0.024)($912,575) = $21,902 ≈ $22,000.
• C is incorrect as it uses an incorrect base value: (0.024)($1,000,000) = $24,000.