A: `Ce^(+4)` is a good oxidizing agent.
R: `Sm^(+2)` is a good reducing agent

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To analyze the given statements regarding cerium and samarium, we can break down the reasoning step by step.

### Step 1: Understand the Assertion
The assertion states that `Ce^(+4)` is a good oxidizing agent.

- **Explanation**: In the case of cerium, its most stable oxidation state is +4. This means that cerium in the +4 oxidation state has a tendency to gain electrons to revert to a lower oxidation state, which is +3. The ability to gain electrons indicates that it can oxidize other substances while itself being reduced. Therefore, cerium in the +4 state acts as a good oxidizing agent.

### Step 2: Understand the Reason
The reason states that `Sm^(+2)` is a good reducing agent.

- **Explanation**: For samarium, its maximum oxidation state is +3. When samarium is in the +2 oxidation state, it has the tendency to lose an electron to reach the +3 state. This process of losing electrons is characteristic of a reducing agent, as it reduces another substance by donating electrons. Hence, samarium in the +2 state is indeed a good reducing agent.

### Conclusion
Both the assertion and the reason are correct. Therefore, the correct answer is that both statements are true.

### Final Answer
- **Assertion (A)**: `Ce^(+4)` is a good oxidizing agent. (True)
- **Reason (R)**: `Sm^(+2)` is a good reducing agent. (True)