This is a communicable disease

The correct option is Rabies.

To understand why this is the correct answer, let us define what a communicable disease is and analyze each option step-by-step:

1. What is a Communicable Disease?
A communicable disease (also known as an infectious disease) is an illness caused by a specific infectious agent or its toxic products. It can be transmitted directly or indirectly from an infected person, animal, or environment to a susceptible host.

2. Analyzing the Options:
• Rabies: Rabies is a viral disease caused by the rabies virus (a Lyssavirus). It is transmitted to humans and other animals through the bite or scratch of an infected animal (most commonly dogs, bats, or wild animals). Because it is caused by a pathogen (virus) and can be transmitted from one host to another, it is classified as a communicable disease.
• Cancer: Cancer is a non-communicable disease characterized by the uncontrolled division of abnormal cells in the body. It is caused by genetic mutations, environmental factors, or lifestyle choices, and cannot be transmitted from person to person.
• Alkaptonuria: This is a rare inherited genetic disorder where the body cannot produce enough of an enzyme called homogentisic acid oxidase. It is a non-communicable, hereditary metabolic disorder.
• Phenylketonuria (PKU): Like Alkaptonuria, PKU is an inherited genetic metabolic disorder characterized by the body's inability to metabolize the amino acid phenylalanine. It is non-communicable and passed down genetically from parents to offspring.

Therefore, among the given choices, Rabies is the only disease that can be transmitted from an infected organism to another, making it a communicable disease.