Final answer:
The income deficit is $3,000 and the ratio of income to poverty is 0.875. Therefore, the correct option is D.
Step-by-step explanation:
The income deficit is calculated by subtracting the family's income from the poverty threshold. In this case, the income deficit would be $24,000 - $21,000 = $3,000.
The ratio of income to poverty is calculated by dividing the family's income by the poverty threshold. In this case, the ratio of income to poverty would be $21,000 / $24,000 = 0.875.
Therefore, the correct answer is d) $3,000; 0.875.