Golden rice is.

Options

A. a variety of rice grown along the yellow river in China.
B. long stored rice having yellow colour tint.
C. a transgenic rice having gene for `beta` -carotene.
D. wild variety of rice with yellow coloured grains.

Explanation

**Step-by-Step Solution:**

1. **Identify Golden Rice**: Golden rice is a specific variety of rice that has been genetically engineered to contain a significant amount of beta-carotene.

2. **Understanding Beta-Carotene**: Beta-carotene is a precursor to vitamin A, meaning that it can be converted by the body into vitamin A as needed. This is important for human health, particularly for vision and immune function.

3. **Genetic Engineering Aspect**: Golden rice is produced through genetic engineering, which involves inserting genes into the rice plant that enable it to produce beta-carotene. This process makes golden rice a transgenic organism.

4. **Evaluate the Options**:
- **Option 1**: "Variety of rice grown along the yellow river in China." - This is incorrect as it does not describe golden rice.
- **Option 2**: "Long stored rice having yellow color tint." - This is also incorrect as it does not pertain to the genetic modification aspect.
- **Option 3**: "A transgenic rice having gene for beta-carotene." - This is correct as it accurately describes golden rice.
- **Option 4**: "A wild variety of rice with yellow colored grains." - This is incorrect as it does not reflect the genetic engineering involved in golden rice.

5. **Conclusion**: The correct answer is option 3, which states that golden rice is a transgenic rice having a gene for beta-carotene.