If the plant is infected with one diseae, it makes the plant resistant to other disease. This phenomenon is known as

Answer: Option C

If the plant is infected with one disease, it makes the plant resistant to other diseases. This phenomenon is known as Cross protection.
Cross-protection, also known as “pre-immunization" is a method of plant virus control, whereby a plant is deliberately infected with a mild strain of a virus to protect the plant against damage caused by a more severe strain of the same virus.