The size of Spirochete is approximately?

Explanation

The correct answer is Option D: 500 μm. Spirochetes are known for their unique spiral shape and can vary significantly in size. While most bacteria are much smaller, some spirochetes can indeed reach lengths of up to 500 micrometers, making them among the largest known bacteria. Option A (0.75-1.25 μm) is more typical of many smaller bacterial species. Option B (100-200 nm) is incorrect as it falls within the size range of viruses, not bacteria. Option C (0.1-600 μm) is overly broad and not specific to spirochetes.