Declining living standards drive population fall Steps:

• Evaluate access to healthy diet: falling access raises mortality rates via poorer health and nutrition.
• Evaluate cost of bringing up children: falling costs signal economic decline, amplifying hardship and outweighing any fertility boost.
• Compare options: identify where both factors worsen to maximize population decline risk.
• Select option with dual negative trends for highest likelihood of falling population.

Why B is correct:

• Both falling access to healthy diet and falling child-rearing costs indicate severe economic deterioration, per demographic transition theory, where high mortality from poverty exceeds fertility gains, causing net population decline.

Why the others are wrong:

• A: Rising child costs reduce births but falling diet alone may not dominate enough for clear decline.
• C: Rising diet lowers deaths while falling costs boost births, promoting growth.
• D: Rising diet improves health; rising costs curb births but low mortality sustains or grows population.

Final answer: B