Correct option is B
The structure "not only... but also" is used to link two ideas, and the word order must ensure that the sentence flows naturally. In this case, "not only" should come before the first adjective, and "but also" should connect the second adjective.
Option (A): "Not only the man was foolish but also tactless." – Incorrect because the subject "the man" should come after "was."
Option (B): "The man was not only foolish but also tactless." – Correct because it follows the correct structure and maintains clarity.
Option (C): "The man was foolish not only but also tactless." – Incorrect word order; the placement of "not only" disrupts the sentence flow.
Option (D): "The man not only was foolish but also tactless." – Incorrect word order; the verb "was" should come after the subject "the man."