In the following question, out of the four alternatives, select the word which is most opposite in meaning to the given word: Differ.

Introduction / Context:
This antonym question tests your understanding of the verb differ, which is commonly used in discussions and debates. Knowing both its meaning and its opposite helps you follow arguments and express agreement or disagreement clearly in English.

Given Data / Assumptions:

• Target word: Differ.
• Options: Alter, Concur, Digress, Vary.
• Typical usage: “I differ from you on this point” means “I disagree with you on this point.”
• We must find the word whose meaning is opposite to differ in the context of opinions.

Concept / Approach:
Differ generally means to be unlike, or in the context of opinions, to disagree. The opposite of disagree is to agree. Concur means to agree with someone or share the same opinion. Alter means change, digress means to wander away from the main topic, and vary means to be different or change slightly. Only concur directly expresses agreement and therefore stands as the antonym of differ in this context.

Step-by-Step Solution:
Identify the key sense of differ in this question: differ in opinion = disagree.Look for a word that means agree or have the same view.Concur is a formal verb meaning to agree or to have the same opinion as someone.Alter and vary both relate to change or difference and are not opposites of differ.Digress refers to moving away from the main subject in speech or writing, which again does not mean the opposite of differ.Therefore, Concur is the correct antonym of Differ.

Verification / Alternative check:
Compare sentences: “I differ from you on this issue” versus “I concur with you on this issue.” The first means “I disagree,” and the second means “I agree,” showing a direct opposition in meaning. If we replace differ with alter or vary, we do not get a clear statement about agreement or disagreement. Digress would change the meaning entirely to losing focus in conversation, not to agreeing or disagreeing.

Why Other Options Are Wrong:
Alter means to change something, not to agree. Vary means to change or be different, and in many contexts it is close to differ instead of being opposite to it. Digress describes a speaker or writer moving away from the main topic, not the relationship between two opinions. None of these verbs expresses the idea of sharing the same view, which is what we need as an antonym of differ in this question.

Common Pitfalls:
Because differ can mean “to be different,” some students are tempted by vary or alter, thinking that the opposite is “remain the same.” However, vocabulary questions often focus on the most exam relevant sense, which here is “differ in opinion” = “disagree”. The natural opposite in that context is “agree”, and the more formal, exam friendly verb for that is concur. Remember this pair: differ (disagree) vs concur (agree).

Final Answer:
The antonym of “Differ” in this context is Concur.