Which of the following options has an odd pair ?

Options

A. Sting of honey bee and scorpion
B. Wing of an insect and bat
C. Stipules of Lathyrus and petiole of Acacia
D. Forelimbs of frog and human

Answer

To solve the question "Which of the following options has an odd pair?" we need to analyze the pairs provided in the options and identify which one does not fit with the others based on the concept of analogous and homologous organs.

### Step-by-Step Solution:

1. **Understanding Analogous Organs**:
- Analogous organs are those that have different structures but perform similar functions. For example, the wings of insects and bats are analogous because they serve the same function (flight) but are structurally different.

2. **Analyzing the First Option**:
- The first option mentions two organs that are analogous. If they are structurally different and perform similar functions, they belong to the category of analogous organs. Therefore, this option is not the odd pair.

3. **Analyzing the Second Option**:
- The second option also refers to the wings of an insect and a bat. As discussed, these are also analogous organs. Thus, this option is also not the odd pair.

4. **Analyzing the Third Option**:
- The third option mentions the stipules of Lathyrus and the petiole of Acacia. Stipules and petioles are both parts of plants but serve different functions. This means they are not analogous or homologous in the same sense as the previous examples. However, they do not fit the criteria for being an odd pair based on the context provided.

5. **Analyzing the Fourth Option**:
- The fourth option discusses the forelimb of a frog and a human. These are homologous organs because they have a similar structure (both are forelimbs) but serve different functions (the frog uses its limbs for swimming while humans use theirs for manipulation). This makes this option the odd pair compared to the others.

### Conclusion:
The correct answer is the fourth option: the forelimb of a frog and a human, as it represents homologous organs, while the others represent analogous organs.