The software is not efficient.
Efficiency generally refers to how quickly a process can be completed with the resources available, and in this case, the delay in displaying the price indicates a lack of efficiency in the software's performance.
The other options:
- Robust refers to the software's ability to handle errors and operate under various conditions, not specifically related to speed.
- Mitigated refers to reducing the severity or seriousness of something, which doesn't apply directly to the performance issue at hand.
- Secure relates to the safety and protection of data, which is also not the primary concern in this scenario.