Final answer:
A disadvantage of push systems in the supply chain is that they result in higher costs when forecasting sales is difficult. So, the correct answer is option d.
Step-by-step explanation:
A disadvantage of push systems is that they result in higher costs when forecasting sales is difficult. In a push system, products are produced and pushed through the supply chain based on sales forecasts. When the sales forecast is inaccurate or uncertain, there is a risk of producing too much or too little, leading to higher costs and potential inefficiencies.
So, the correct answer is option d.