What type of compression retains all the information while reducing file size?

Lossless compression is a method that reduces the size of a file without losing any information. This type of compression allows the original data to be perfectly reconstructed from the compressed data. It is particularly important in scenarios where retaining every detail is crucial, such as with text files, executable files, or certain types of images, like PNGs.

In lossless compression, algorithms identify and eliminate redundancies within the data without discarding any actual content. When the file is decompressed, it returns to its original form, maintaining the integrity of the information. This characteristic is why lossless compression is essential in various applications where accuracy is necessary, such as in software development, data storage, and high-quality media.

In contrast, other forms of compression, like lossy compression, reduce file size by removing some information, which is not ideal for applications requiring full fidelity. Other terms, such as adaptive and static compression, refer more to the methodologies or specific characteristics of compression techniques rather than to the preservation of data integrity. Thus, lossless compression is the correct choice for retaining all information while reducing file size.