Concept:In passive voice transformation of an interrogative sentence, the object becomes the new subject, the helping verb moves before the subject, and the main verb changes to its past participle form.
Explanation:The active sentence has "we" as the subject, "have had" as the verb, and "a series of talks with Fowler" as the object.
First, the object is made the new subject of the passive sentence.
Since "a series of talks with Fowler" is singular, the helping verb changes from "have" to "has".
Next, the main verb "had" is converted into the passive form "been had".
The original subject "we" becomes the agent and takes the objective case "us", preceded by "by".
Because the sentence is interrogative, the helping verb "has" is placed at the beginning, before the new subject.
This gives the correct passive sentence: "Has a series of talks with Fowler been had by us?"
Option A is incorrect because "Have" does not agree with the singular subject.
Options B and D are incorrect because they use "Had been" instead of "Has been".
Answer:Option C: Has a series of talks with Fowler been had by us?