During inspiration, the external intercostal muscles and diaphragm contract. This statement is correct. Let's understand why this is the correct answer.

The process of breathing involves two main phases: inspiration (inhaling) and expiration (exhaling). During inspiration, the diaphragm and external intercostal muscles play a crucial role.

1. Inspiration:
- The diaphragm is a dome-shaped muscle located at the base of the lungs. When it contracts, it moves downward, causing the volume of the thoracic cavity to increase.
- The external intercostal muscles are located between the ribs. When they contract, they lift the ribcage upward and outward, further expanding the thoracic cavity.
- The expansion of the thoracic cavity leads to a decrease in pressure within the lungs, creating a pressure gradient between the atmosphere and the lungs.
- As a result, air flows from an area of higher pressure (the atmosphere) to an area of lower pressure (the lungs), filling the lungs with oxygen.

2. Cyanosis:
- Cyanosis refers to a bluish discoloration of the skin, mucous membranes, and nails. It occurs when there is a decrease in oxygen levels in the blood.
- Cyanosis is not directly related to the collapse of alveoli. Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place. The collapse of alveoli is known as atelectasis, and it can lead to respiratory distress, but it does not cause cyanosis.

3. Eupnea:
- Eupnea refers to normal, unlabored breathing. It is characterized by a regular rate and depth of breathing.
- Eupnea is not slow breathing. Slow breathing is known as bradypnea, and it can be caused by certain medical conditions or medications.

4. Coryza:
- Coryza, also known as the common cold, is an infection of the upper respiratory tract. It is not caused by human coronavirus alone.
- Coryza can be caused by various viruses, including rhinoviruses, coronaviruses, and adenoviruses, among others.

In conclusion, the correct statement is that during inspiration, the external intercostal muscles and diaphragm contract. This action expands the thoracic cavity, creating a pressure gradient that allows air to flow into the lungs.

A is the correct option