Assertion: In prokaryotes, there is present a ring shaped chromosome.
Reason: The ring shaped chromosome is called Eukaryotic Nucleus.

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

To solve the assertion and reason question, we can follow these steps:

### Step 1: Analyze the Assertion
- The assertion states: "In prokaryotes, there is present a ring-shaped chromosome."
- This is true. Prokaryotes, such as bacteria, possess a single, circular chromosome that is not enclosed in a membrane. This structure is referred to as the nucleoid.

### Step 2: Analyze the Reason
- The reason states: "The ring-shaped chromosome is called Eukaryotic Nucleus."
- This statement is false. The eukaryotic nucleus is a membrane-bound organelle that contains linear chromosomes, not a ring-shaped chromosome. In eukaryotes, the DNA is organized into multiple linear chromosomes within the nucleus.

### Step 3: Determine the Relationship Between Assertion and Reason
- Since the assertion is true and the reason is false, we conclude that the correct relationship is that the assertion is correct, but the reason is incorrect.

### Step 4: Choose the Correct Answer
- Based on the analysis, the correct answer is that the assertion is true and the reason is false. Therefore, the answer is option 3.

### Summary of the Solution
- Assertion: True (Prokaryotes have a ring-shaped chromosome).
- Reason: False (The ring-shaped chromosome is not called the eukaryotic nucleus).
- Conclusion: Assertion is correct, reason is incorrect.