Answer:
Evidence.
Step-by-step explanation:
An argumentative essay is an essay that makes a student to do extensive research on a topic and establish an argument presented from the both sides. To write an effective argumentative essay, one must included a thesis statement in the first paragraph, smooth transition between the paragraphs, evidential support that is logical and factual, and a conclusion.
So, to make an argumentative essay appear effective the writer must include an evidence in support of a claim. An evidence needs to be logical, factual, statistical, and reliable.
An evidence can be defined as a information that supports the assertion of a claim. This can be in the form of a quote, statistics, etc.
Thus from the given options the correct one is evidence.