Answer: D. $12,359,424$

Explanation:1. Understand the given information and the required conversion: Area of a town = $3.99$ square miles. We need to find the area in square yards. Conversion factor: $1 \text{ mile} = 1,760 \text{ yards}$.

2. Determine the conversion factor for square units: If $1 \text{ mile} = 1,760 \text{ yards}$, then $1 \text{ square mile} = (1 \text{ mile}) \times (1 \text{ mile})$ $1 \text{ square mile} = (1,760 \text{ yards}) \times (1,760 \text{ yards})$ $1 \text{ square mile} = (1,760)^2 \text{ square yards}$.

3. Calculate $(1,760)^2$: $(1,760)^2 = 1760 \times 1760$. $176 \times 176$: $176 \times 100 = 17600$ $176 \times 70 = 12320$ $176 \times 6 = 1056$ Sum = $17600 + 12320 + 1056 = 29920 + 1056 = 30976$. So, $(1760)^2 = 3097600$. Therefore, $1 \text{ square mile} = 3,097,600 \text{ square yards}$.

4. Convert the area of the town to square yards: Area in square yards = Area in square miles $\times$ (Number of square yards per square mile) Area in square yards = $3.99 \times 3,097,600$.

5. Perform the multiplication: $3.99 \times 3,097,600 = (4 - 0.01) \times 3,097,600$ $= 4 \times 3,097,600 - 0.01 \times 3,097,600$ $4 \times 3,097,600 = 12,390,400$. $0.01 \times 3,097,600 = 30,976$. Area in square yards = $12,390,400 - 30,976$. $12,390,400 - 30,976 = 12,359,424$.

6. Compare with the given options: [A] $441$ [B] $7,022$ [C] $776,341$ [D] $12,359,424$ - This matches our result.

7. Conclusion: The area of the town is $12,359,424$ square yards.