Concept:
In English grammar, subject–verb agreement plays a crucial role in determining the correctness of a sentence. According to this rule, the verb must agree with the number (singular or plural) of the subject. However, there are special cases where the grammatical form of the subject may appear plural, but it is treated as singular in meaning. One such important case is the naming of titles of books, novels, films, poems, newspapers, and other literary or artistic works.
Step 1: Identify the subject clearly in the sentence.
The subject of the sentence is:
\[
\text{“A Tale of Two Cities”}
\]
At first glance, the phrase appears plural because it contains the word “Cities”. However, it is important to understand that this is not a general noun phrase; it is the title of a specific novel written by Charles Dickens. Therefore, the subject refers to a single literary work as a complete entity.
Step 2: Apply the grammatical rule for titles.
According to standard English grammar rules:
• Titles of books, novels, films, poems, paintings, and newspapers are always treated as singular nouns.
• Even if the title contains plural-looking words, it is still considered a single unit.
Thus, “A Tale of Two Cities” represents one novel, not multiple cities or multiple works. Hence, it must take a singular verb.
Step 3: Analyze the given options logically.
We check each option:
• (A) are — plural verb, incorrect because the subject is singular.
• (B) were — past plural form, incorrect for the same reason.
• (C) is — singular present tense verb, grammatically correct.
• (D) have been — present perfect plural form, incorrect.
Step 4: Construct the correct sentence.
By applying the correct subject–verb agreement rule, the sentence becomes:
\[
\text{A Tale of Two Cities is written by Charles Dickens.}
\]
This sentence is grammatically correct because the singular verb “is” correctly matches the singular subject (the title of the novel).
Final Answer:
\[
\boxed{\text{is}}
\]