The correct answer is option 1 - "Intelligent persons have good memory". This hypothesis is both testable and refutable.

1. We can test it by measuring the memory capacity of individuals who have been classified as intelligent based on certain criteria. We could use various memory tests to do this. If the results show that these individuals generally have a better memory than others, then the hypothesis is supported.

2. The hypothesis is refutable because we could potentially find intelligent individuals who do not have a good memory, thus proving the hypothesis wrong.

Option 2, "Some birds are animals", and option 4, "All men are mortal", are not hypotheses but facts accepted universally and hence, they can`t be refuted.

Option 3, "Some businessmen are dishonest", is too vague and subjective to test properly as `dishonesty` would need to be clearly defined and measured. Thus it partially lacks the criteria needed for a hypothesis.