Step 1: Understanding the Task
The task is to find the correct question tag for the given statement.
Step 2: Applying the Rules of Question Tags
We apply the positive-negative flip rule and match the verb and pronoun.
Step 3: Detailed Explanation
The main statement is "Somebody has informed...". This is a positive statement.
Therefore, the question tag must be negative.
The auxiliary verb is "has". The negative form is "hasn't".
The subject is "Somebody". Indefinite pronouns like somebody, someone, everybody, everyone, nobody are treated as singular in the main statement but are referred to by the plural pronoun "they" in the question tag.
When the pronoun is "they," the auxiliary verb must also be plural. The plural form of "hasn't" is "haven't".
Combining the negative plural auxiliary verb and the plural pronoun gives the tag: "haven't they?".
Step 4: Final Answer
The statement is positive ("has"), so the tag is negative ("haven't"). The subject "Somebody" takes the pronoun "they". Therefore, the correct tag is "Haven't they?". Option (C) is the correct answer.