Select the correct option:
Each of the datasets ____________ been anonymized before release.

Correct option is B

The correct option to fill in the blank is (b) has.
Explanation of correct answer: The subject is “Each”, which is singular, so it takes a singular verb. Therefore, the correct verb phrase is has been anonymized. (Hindi meaning of “anonymized”: गुमनाम किया गया / पहचान हटाई गई)
Example: Each of the files has been verified by the auditor.
Explain why other options are incorrect:
• (a) have: plural verb; mismatches the singular subject “Each.”
• (c) are: wrong tense and structure; passive needs “has been,” not “are been.”
• (d) were: past tense and also plural; the sentence needs present perfect passive (“has been”).