Transgenic Brassica napus has been used for the synthesis of:

Options

A. Hirudin
B. Heparin
C. Polygalacturonase
D. Cry protein

Answer

To answer the question "Transgenic Brassica napus has been used for the synthesis of:", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**: Start by recognizing that Brassica napus is a species of plant commonly known as rapeseed or canola. It belongs to the family Brassicaceae.

2. **Understand Transgenic Plants**: Transgenic plants are genetically modified organisms (GMOs) that have had a foreign gene inserted into their genome. This is done to express a specific trait or produce a particular substance.

3. **Research the Purpose of Transgenic Brassica napus**: Transgenic Brassica napus has been developed to produce various proteins, one of which is hirudin. Hirudin is a protein that acts as an anticoagulant, preventing blood clotting.

4. **Source of Hirudin**: Hirudin is naturally found in the saliva of leeches. The gene responsible for producing hirudin has been isolated and inserted into the genome of Brassica napus to enable the plant to synthesize this protein.

5. **Evaluate the Options**: The options provided are:
- A) Hirudin
- B) Heparin
- C) Polygalacturonase
- D) Cryoprotein

Among these, hirudin is the correct answer since transgenic Brassica napus has been specifically engineered to produce this protein.

6. **Conclusion**: Therefore, the correct answer to the question is that transgenic Brassica napus has been used for the synthesis of hirudin.

### Final Answer:
Transgenic Brassica napus has been used for the synthesis of **hirudin**.