Respiratory Disorders and Occupational Respiratory Disorders:
Respiratory disorders are medical conditions that affect the respiratory system, which includes the lungs, airways, and other structures involved in breathing. Occupational respiratory disorders are specifically caused or aggravated by exposure to certain substances or conditions in the workplace.

Identifying Occupational Respiratory Disorders:
Let's analyze each of the given respiratory disorders to identify the occupational respiratory disorders among them.

(i) Coryza:
Coryza, commonly known as the common cold, is a viral infection that causes symptoms such as a runny or stuffy nose, sneezing, sore throat, and cough. Coryza is not an occupational respiratory disorder as it is not caused by workplace conditions or exposure.

(ii) SARS:
Severe Acute Respiratory Syndrome (SARS) is a highly contagious viral respiratory illness. It is caused by the SARS-CoV virus and can cause severe pneumonia. SARS is not an occupational respiratory disorder as it is not specifically related to workplace exposure.

(iii) Silicosis:
Silicosis is a chronic lung disease caused by the inhalation of crystalline silica dust. It occurs in workers who are exposed to silica dust, such as those in mining, construction, and sandblasting industries. Silicosis is an occupational respiratory disorder as it is directly related to workplace exposure.

(iv) Asbestosis:
Asbestosis is a chronic lung disease caused by the inhalation of asbestos fibers. It occurs in workers who are exposed to asbestos, such as those in construction, shipbuilding, and asbestos mining industries. Asbestosis is an occupational respiratory disorder as it is directly related to workplace exposure.

(v) Emphysema:
Emphysema is a type of chronic obstructive pulmonary disease (COPD) characterized by the destruction of the air sacs in the lungs. It is commonly caused by long-term exposure to cigarette smoke, air pollution, and other environmental factors. While smoking can be an occupational exposure in some cases, emphysema itself is not considered a specific occupational respiratory disorder.

Conclusion:
After analyzing the given respiratory disorders, it can be concluded that the occupational respiratory disorders among them are Silicosis (iii) and Asbestosis (iv). These disorders are directly caused by workplace exposure to silica dust and asbestos fibers, respectively. Therefore, the correct answer is option 'C' - (iii) and (iv).