ANS:A - a higher capacity

For a cold viscous feed, backward feed gives a higher capacity than forward feed. Explanation:

• In a backward feed configuration, the coldest fluid enters the heat exchanger at the opposite end from where the hot fluid enters. This allows the coldest fluid to absorb more heat along the length of the exchanger before exiting, resulting in a higher capacity to absorb heat.
• In contrast, in a forward feed configuration, the coldest fluid enters at the same end as the hot fluid, and thus may not have as much opportunity to absorb heat before exiting. Therefore, forward feed may have a lower capacity for heat transfer in comparison.
• The statement does not indicate anything about economy, so it cannot be determined whether backward feed has lower or higher economy based on the information provided.
• Therefore, the correct statement is that backward feed gives a higher capacity than forward feed.