Disease resistance crop is obtained by

Options

A. Crossing with new varieties
B. Crossing with wild varieties
C. Injecting with organic compounds
D. None of the above

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks how disease-resistant crops are obtained. This involves understanding the methods used in plant breeding to enhance disease resistance.

2. **Identifying the Methods**: The options provided are:
- A) Crossing with new varieties
- B) Crossing with wild varieties
- C) Injecting with organic compounds
- D) None of the above

3. **Evaluating Each Option**:
- **Option A**: Crossing with new varieties can lead to improved traits, but it may not specifically enhance disease resistance.
- **Option B**: Crossing with wild varieties is a common method used in plant breeding to introduce disease-resistant traits. Wild varieties often possess genes that confer resistance to diseases.
- **Option C**: Injecting with organic compounds is not a standard method for developing disease-resistant crops.
- **Option D**: This option can be ruled out since there are methods available for obtaining disease-resistant crops.

4. **Conclusion**: The most effective method for obtaining disease-resistant crops is by crossing with wild varieties. This method allows for the introduction of beneficial traits from wild relatives into cultivated varieties, enhancing their resistance to diseases.

5. **Final Answer**: Therefore, the correct answer is **B) Crossing with wild varieties**.