What type of software requires low latency for transactions, such as in financial markets?

High-frequency trading applications are designed to execute a large number of orders at extremely high speeds, often measured in microseconds or nanoseconds. This requires low latency in order to capitalize on small price fluctuations in the markets that may occur for very brief periods. The performance of these applications depends significantly on their ability to process and respond to market data with minimal delay, ensuring that trades are executed at the most advantageous prices.

In contrast, batch processing applications handle large volumes of data by processing it in groups (or batches) rather than in real time. This approach is generally not time-sensitive and does not require low latency.

Real-time analysis applications do involve immediate data processing and can be sensitive to latency, but they may not require the same extreme speed and transaction volume that high-frequency trading applications necessitate.

Cloud backup solutions typically focus on data storage and recovery, which do not depend on low-latency conditions but rather on efficient data transfer and reliability. Thus, the requirement for low latency in financial transactions specifically aligns with high-frequency trading applications, making it the correct answer for this question.