In a debate, it is crucial to be ____________ in your arguments to be persuasive.

The adjective "rational" is the correct choice here because it describes a quality that is essential for effectively presenting arguments in a debate. When someone is rational, they are using logic and reason to support their viewpoints, which enhances the persuasiveness of their arguments. In debates, where clear and logical reasoning is pivotal for convincing an audience, being rational allows a debater to articulate their points more effectively and respond to counterarguments with sound reasoning.

The other options do not fit the required form or meaning for the sentence. "Rationality" is a noun and would not appropriately modify the noun "arguments." "Rationalize" is a verb that suggests the act of attempting to justify or explain something, but it does not describe the nature of the arguments themselves. "Irrational," which means lacking reason or logic, would imply the opposite of what is needed for persuasive arguments. Hence, "rational" stands out as the term that correctly captures the necessary quality for effective debate.