A.I. Explanation:

Option 1: "The infection can spread to other parts of the body through the blood vessels."

Explanation: The text states that untreated decay may cause an infection that can spread to other parts of the body through the blood vessels in the pulp or the jaw bone. This directly supports the option, as it highlights the potential for serious illness due to the spread of infection.

Option 2: "The infection majorly goes in the pulp or the jaw bone, causing serious illness."

Explanation: The text mentions that an infection may reach the pulp or underlying bone, which can lead to serious illness. This aligns with the option, as it emphasizes the severity of the infection's impact on the pulp and jaw bone.

Option 3: "The enamel eventually brings out all the blood from the body."

Explanation: This option is incorrect because the text does not mention the enamel bringing out blood from the body. Instead, it focuses on the progression of decay and its effects on the pulp and surrounding areas.

Option 4: "A small sac of infection is found throughout the body parts."

Explanation: This option is incorrect as it misrepresents the information in the text. While it mentions a small sac of pus (abscess), it does not imply that this infection is found throughout the body. The text specifies that the infection can spread, but it does not state that it is widespread throughout the body.

Option 5: "Tooth decay can damage whole mouth."

Explanation: This option is incorrect because the text does not discuss damage to the entire mouth. It specifically addresses the progression of decay into the pulp and the potential for serious illness, rather than general damage to the mouth.