Which one of the following is a CORRECT statement ?

Options

A. 'Bt'' in ''Bt- cotton'' indicates that it is a genetically modified organism produced through biotechnology.
B. Somatic hybridization involves the fusion of two complete plant cells carrying desired genes.
C. RNAi takes place in all eukaryotic organisms as a method of cellular defense.
D. Golden rice is vitamin C enriched rice.

Answer

To determine which statement is correct, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Analyze the first statement about Bt-cotton:**
- Bt-cotton is a genetically modified organism (GMO) that has been modified using biotechnology. The "Bt" stands for Bacillus thuringiensis, a bacterium that produces a toxin harmful to certain pests. Therefore, the statement that "Bt in the Bt-cotton indicates that it is the genetically modified organism produced through biotechnology" is incorrect because it misrepresents the meaning of "Bt".

**Hint:** Remember that "Bt" refers specifically to the bacterium, not the process of genetic modification itself.

2. **Evaluate the second statement regarding somatic hybridization:**
- Somatic hybridization involves the fusion of protoplasts (the living part of a plant cell without the cell wall), not the fusion of complete plant cells. Therefore, this statement is also incorrect.

**Hint:** Focus on the terminology; protoplasts are key in somatic hybridization, not whole cells.

3. **Examine the third statement about RNA interference (RNAi):**
- RNA interference is a biological process in which RNA molecules inhibit gene expression or translation, effectively regulating the mRNA molecules. This process is indeed present in all eukaryotic organisms and serves as a method of cellular defense. Thus, this statement is correct.

**Hint:** Recall that RNAi is a fundamental mechanism of gene regulation in eukaryotes.

4. **Assess the fourth statement about golden rice:**
- Golden rice is genetically modified to produce beta-carotene, a precursor of vitamin A, not vitamin C. Therefore, this statement is incorrect.

**Hint:** Remember the nutritional purpose of golden rice; it is related to vitamin A, not vitamin C.

### Conclusion:
The only correct statement among the options provided is the one about RNA interference (RNAi) taking place in all eukaryotic organisms as a method of cellular defense.

**Final Answer:** The correct statement is about RNAi (option C).