Assertion: Cell was discovered by Robert Hooke.
Reason: All the cells are eukaryotic.

Options

A. If both As and R are correct and R is correct explanation of As
B. If both As and R are correct but R is not correct explanation of As
C. If As is correct, R is wrong
D. If both As and R are wrong.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that "Cell was discovered by Robert Hooke." This is a historical fact. Robert Hooke, in 1665, observed cork under a microscope and described the small box-like structures he saw as "cells." This assertion is correct.

2. **Understanding the Reason**: The reason states that "All the cells are eukaryotic." This statement is incorrect. Cells can be classified into two main categories: prokaryotic and eukaryotic. Prokaryotic cells, which include bacteria and archaea, do not have a membrane-bound nucleus and are generally simpler in structure. Eukaryotic cells, on the other hand, have a membrane-bound nucleus and are found in organisms such as plants, animals, fungi, and protists.

3. **Evaluating the Relationship**: The assertion is correct, but the reason provided is incorrect. Therefore, the reason does not explain the assertion.

4. **Conclusion**: Based on the evaluation, we conclude that the assertion is correct and the reason is incorrect. Thus, the correct option is that the assertion is true and the reason is false.

### Final Answer:
- Assertion: True
- Reason: False
- Conclusion: The assertion is correct, but the reason is incorrect.