Bt toxin is produced by a bacterium called Bacillus thuringiensis ( Bt for short). These Bt toxin crystals contain by a gene named cry which has many variants. Which one from the following produces a toxin that controls corn borer ?

Options

A. CryIAc
B. CryIAb
C. CryIIAb
D. Both (A) and (C)

Answer

To solve the question about which variant of the cry gene produces a toxin that controls corn borer, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**:
- Bacillus thuringiensis (Bt) is a bacterium that produces toxins effective against various insects.
- These toxins are produced in the form of crystals and are encoded by genes known as cry genes.

2. **Identify the Variants of the cry Gene**:
- The question provides several variants of the cry gene: cry1AC, cry1AB, cry2AB, and both E and C.
- Each variant has a specific target insect or group of insects.

3. **Determine the Target of Each Variant**:
- The question specifically asks for the variant that controls corn borer.
- From the information provided, we know that:
- Cry1AB is known to control corn borer.
- Other variants like cry1AC and cry2AB are associated with different pests, such as cotton bollworm.

4. **Select the Correct Variant**:
- Since cry1AB is the variant that targets corn borer, we can conclude that this is the correct answer.

5. **Final Answer**:
- The variant that produces a toxin that controls corn borer is **cry1AB**.