**Core Concept**
The investigation of an epidemic involves a systematic approach to identify the cause, determine the scope of the outbreak, and implement control measures. This process includes several key steps to ensure accurate diagnosis, effective intervention, and public health safety.

**Why the Correct Answer is Right**
The correct answer is one of the options listed below. Each option represents a crucial step in the investigation of an epidemic. However, one of these options does not belong. To determine the correct answer, we need to examine each option in detail.

**Why Each Wrong Option is Incorrect**
**Option A:** This is a critical step in the investigation of an epidemic. It involves the collection and analysis of data to identify the outbreak, its cause, and its scope. This step helps to determine the need for further investigation and the implementation of control measures.

**Option B:** This option is also a crucial step in the investigation of an epidemic. It involves the collection of data from various sources, including clinical records, laboratory reports, and surveillance systems. This step helps to identify the outbreak, its cause, and its scope, and to determine the need for further investigation and control measures.

**Option C:** This option is not a step in the investigation of an epidemic. It is more related to the implementation of control measures rather than investigation. Control measures are implemented after the cause of the outbreak has been determined and the scope of the outbreak has been identified.

**Clinical Pearl / High-Yield Fact**
In the investigation of an epidemic, it is essential to identify the cause of the outbreak as soon as possible. This can be achieved by analyzing data from various sources, including clinical records, laboratory reports, and surveillance systems.

**Correct Answer: C. Control measures are implemented after the cause of the outbreak has been determined and the scope of the outbreak has been identified.