[A]: Cycads were prevalent during Jurassic period.
[R]: Jurassic period is considered as Age of cycads

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

To solve the question regarding the assertion and reason about cycads and the Jurassic period, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Assertion and Reason**:
- Assertion (A): Cycads were prevalent during the Jurassic period.
- Reason (R): The Jurassic period is considered the Age of Cycads.

2. **Evaluate the Assertion**:
- The assertion states that cycads were prevalent during the Jurassic period. This is true. Cycads are a group of gymnosperms that thrived during this time and were an important part of the flora.

3. **Evaluate the Reason**:
- The reason states that the Jurassic period is considered the Age of Cycads. This is also true. The Jurassic period is indeed recognized for the dominance of cycads among other plants.

4. **Determine the Relationship**:
- Now, we need to see if the reason correctly explains the assertion. Since cycads were a significant part of the vegetation during the Jurassic period, and their prevalence is what defines this period as the Age of Cycads, the reason does provide a correct explanation for the assertion.

5. **Conclusion**:
- Both the assertion and reason are true, and the reason is the correct explanation of the assertion. Therefore, the answer is:
- **Option 1**: If both assertion and reason are true and reason is the correct explanation of the assertion.

### Final Answer:
- The correct option is **1**: Both assertion and reason are true, and reason is the correct explanation of the assertion.

---