Explanation:

- Start by calculating the work rate:

- 16 boys can complete the work in 28 days.

- Hence, 1 boy can complete the work in $28\times 16=448$ boy-days.

- Similarly, 12 women can complete the work in 28 days.

- Hence, 1 woman can complete the work in $28\times 12=336$ woman-days.

- Calculate the combined work rate:

- If 1 boy does $\frac{1}{448}$ of work per day, then 4 boys do $\frac{4}{448}=\frac{1}{112}$ of work per day.

- If 1 woman does $\frac{1}{336}$ of work per day, then 4 women do $\frac{4}{336}=\frac{1}{84}$ of work per day.

- Work done by 4 boys and 4 women together:

- Combined work rate = $\frac{1}{112}+\frac{1}{84}=\frac{3}{336}+\frac{4}{336}=\frac{7}{336}=\frac{1}{48}$.

- Time taken for all to complete the work:

- Thus, they will complete the work in 48 days.

- Correct Answer:

- Option 2: 48 days

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