Bacillus anthracis, Clostridium botulinum, and Yersinia Pestis are all microorganisms that can be used as bio weapons. However, Escherichia coli (E. coli) is not typically associated with bio weapons.

Explanation:

1. Bacillus anthracis:
- Bacillus anthracis is the bacterium responsible for causing anthrax, a serious infectious disease.
- This bacterium can form spores that are highly resistant to environmental conditions.
- These spores can survive for long periods of time and can be used as a bio weapon.
- Inhaled anthrax is the most lethal form of the disease and can be used in bioterrorism.

2. Clostridium botulinum:
- Clostridium botulinum is a bacterium that produces a potent neurotoxin called botulinum toxin.
- This toxin is one of the most potent toxins known to humans and can cause severe illness or death.
- It can be used as a bio weapon by intentionally contaminating food or water supplies with the toxin.
- The toxin can cause botulism, a rare but serious illness that affects the nervous system.

3. Yersinia Pestis:
- Yersinia pestis is the bacterium responsible for causing bubonic, septicemic, and pneumonic plague.
- The pneumonic form of the disease is highly contagious and can be spread through respiratory droplets.
- This bacterium has been used as a bio weapon in the past, such as during World War II.
- It can be aerosolized and released into the air to infect a large number of people.

4. Escherichia coli (E. coli):
- Escherichia coli is a common bacterium that is found in the intestines of humans and animals.
- While E. coli strains can cause foodborne illnesses, urinary tract infections, and other infections, it is not typically associated with bio weapons.
- E. coli is commonly used in scientific research and is not considered a high-risk agent for bioterrorism.

In conclusion, out of the given options, Escherichia coli (E. coli) is not related to bio weapons. The other options, Bacillus anthracis, Clostridium botulinum, and Yersinia Pestis, are all potential bio weapons due to their ability to cause severe diseases and their potential for intentional use in bioterrorism.