Option 1 states that both the assertion and the reason are true and that the reason correctly explains the assertion. This would imply that radio waves bend in a magnetic field because they are electromagnetic in nature. However, this is incorrect, as electromagnetic waves, including radio waves, do not bend in a magnetic field.

Option 2 suggests that both statements are true, but the reason does not explain the assertion, which is not true because the assertion (A) is false.

Option 3 implies that the radio waves bend in a magnetic field, but they are not electromagnetic. This is incorrect because radio waves are indeed electromagnetic, but they don`t bend in a magnetic field.

Option 4, the correct answer, suggests that radio waves do not bend in a magnetic field, which is true. Furthermore, the fact that radio waves are electromagnetic in nature is also accurate. Thus, the assertion is false, and the reason is true.