Which statement describes lossy compression?

Which statement describes lossy compression?

• A. It compresses the file size by discarding some data
• B. It preserves all original data
• C. It cannot be reversed to recover the exact original data
• D. It increases data quality

Answer: (C)

Lossy compression reduces a file’s size by permanently discarding some information that’s deemed less important for typical use. Because that data is removed, you can’t reconstruct the exact original after decompression. That irreversibility is what makes the statement describing it as unable to recover the exact original data the best fit. Note that saying it preserves all original data would be true for lossless compression, not lossy. And while lossy compression can shrink files, it doesn’t improve quality; in fact, it may reduce quality, even if the loss isn’t easily noticeable.

Lossy compression reduces a file’s size by permanently discarding some information that’s deemed less important for typical use. Because that data is removed, you can’t reconstruct the exact original after decompression. That irreversibility is what makes the statement describing it as unable to recover the exact original data the best fit.

Note that saying it preserves all original data would be true for lossless compression, not lossy. And while lossy compression can shrink files, it doesn’t improve quality; in fact, it may reduce quality, even if the loss isn’t easily noticeable.