Option 1 is the correct answer. In this scenario, both assertion (A) and reason (R) are correct. Assertion A states that amoeba is reproduced by fission, which is accurate. Fission is a type of asexual reproduction used by unicellular organisms where an organism splits into two or more organisms. Reason R states that all unicellular organisms reproduce by asexual methods. This is true because unicellular organisms like the amoeba do not have specialized reproductive cells, so they reproduce asexually. Thus, both the assertion and reason are correct, and the reason correctly explains why the assertion is true. The other options are incorrect as they either claim one statement is false or that the reason does not explain the assertion, both of which are not correct in this case.