Which of the following is incorrect

Options

A. Mango and coconut are drupe fruit
B. According to Euro norm IV sulphur content for petrol is 50 ppm
C. `CO_2` and other poisonous gases cause pollution
D. Apple is a true fruit

Answer

To solve the question "Which of the following is incorrect," we need to evaluate each of the provided options regarding their accuracy.

### Step-by-Step Solution:

1. **Evaluate Option A: Mango and Coconut are True Fruits**
- Mango and coconut are indeed classified as true fruits. They develop from the ovary of the flower and have a structure that includes the pericarp (which consists of the exocarp, mesocarp, and endocarp). Therefore, this statement is **correct**.

2. **Evaluate Option B: According to Euro Norm 4, Sulphur Content of Petrol is 50 ppm**
- Euro Norm 4 refers to European emission standards, which set limits on the amount of pollutants in vehicle emissions. The sulphur content limit for petrol under Euro Norm 4 is indeed 50 parts per million (ppm). Thus, this statement is **correct**.

3. **Evaluate Option C: Carbon Dioxide and Other Poisonous Gases Cause Pollution**
- Carbon dioxide (CO2) is a greenhouse gas that contributes to global warming, and other gases such as nitrogen oxides and sulfur oxides are known pollutants. Therefore, this statement is also **correct**.

4. **Evaluate Option D: Apple is a True Fruit**
- An apple is not classified as a true fruit; it is considered a false fruit (or accessory fruit) because the fleshy part of the apple develops mainly from the thalamus (the thickened part of the stem) rather than solely from the ovary. Therefore, this statement is **incorrect**.

### Conclusion:
The incorrect statement among the options provided is **Option D: Apple is a true fruit**.

### Final Answer:
**Option D is incorrect.**

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