The interval between infection and appearance of a disease is known as?
A) Inoculation
B) Penetration
C) Infection period
D) Incubation period

Hint: It is the time period where the pathogen multiplies itself to make several copies and after multiplication, the organism has disease-causing capacity. A single pathogen does not have that much pathogenicity.

Complete step-by-step answer:

Inoculation is a process in which a microorganism is introduced into a growth medium for its growth for example – microorganisms like lactobacillus and lactic acid bacteria grow in milk and convert it to curd. A small amount of curd is added to fresh milk as an inoculum or starter which at a suitable temperature multiplies and converts milk to curd.
Penetration is a part of the replication or life cycle of viruses. It is the act or power to penetrate. After the virions get attached to the host cell, some conformational changes occur in the capsid protein or phospholipids that result in the fusion of the viral protein with the host cell membranes. Some viruses also enter the host cell through endocytosis.
Infection: When the pathogen or germs invade our body and multiply themselves. The germs can be bacteria, viruses, fungi, yeast, or other microorganisms. Infection can be anywhere in the body and can spread throughout the body. Infection severity can range from mild to fatal. Bacterial infections and viral infections have many things in common. Both are caused by microbes.
The incubation period is a characteristic of a particular disease. There is a minimum period below which the is no illness. It can vary from person to person for the same disease. In some disease incubation period is too small i.e., from a few hours to 2-3 days.

Therefore the correct answer is Option A.
Note: Salmonella- 12-72 hours after infection; symptoms usually resolve in 5-7 days, unless the infected person is in very weakened health status. Measles- it ranges from 10-12 days ( prodomal-i.e., the interval between the earliest symptoms and the appearance of rash or fever.