Carcinoma refers to:

Options

A. malignant tumours of the colon
B. benign tumours of the connective tissue
C. malignant tumours of the connective tissue
D. malignant tumours of the skin or mucous membrane

Explanation

### Step-by-Step Solution:

1. **Understanding Carcinoma**: Carcinoma is a type of cancer that specifically refers to malignant tumors. It originates from epithelial tissues, which are the cells that line the surfaces of organs and structures throughout the body.

2. **Identifying the Characteristics of Carcinoma**:
- **Malignant Nature**: Carcinomas are malignant, meaning they can invade nearby tissues and spread to other parts of the body.
- **Origin**: They arise from epithelial cells, which can be found in various organs, including the skin, lungs, liver, and kidneys.

3. **Types of Tumors**:
- **Malignant Tumors**: These are cancerous and can spread to other parts of the body.
- **Benign Tumors**: These are non-cancerous and do not spread. Carcinomas are not benign.

4. **Examples of Carcinoma**: Common examples include:
- **Basal Cell Carcinoma**: A type of skin cancer.
- **Squamous Cell Carcinoma**: Another skin cancer.
- **Adenocarcinoma**: A type of carcinoma that originates in glandular tissue.

5. **Conclusion**: Given the options provided in the question, carcinoma specifically refers to malignant tumors of the skin and mucous membranes.

### Final Answer:
Carcinoma refers to **malignant tumors of skin and mucous membrane**.

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