Choose the punctuation mark that will replace the * mark in the following sentence.

What happened then * I do not know.

Correct option is D

The correct punctuation mark to replace the * is (d) ; (semicolon).
Correct sentence: What happened then; I do not know.
Detailed Explanation (English): A semicolon (;) is used to connect two closely related independent clauses that could stand as separate sentences but are better joined to show a close relationship. In this sentence, “What happened then” and “I do not know” are both independent clauses. They are related ideas — the second clause explains the speaker’s lack of knowledge about the first — so a semicolon is the most appropriate punctuation mark.
Grammatical rule used: Use a semicolon (;) between two independent clauses not joined by a conjunction (like and, but, because) but having a close relationship in meaning.
Explanation of the grammatical rule in Hindi: जब दो स्वतंत्र वाक्य (independent clauses) आपस में जुड़े हुए अर्थ रखते हैं लेकिन conjunction (जैसे and, but) से नहीं जुड़े होते, तब उनके बीच semicolon (;) लगाया जाता है। उदाहरण: He came late; the meeting had already started.
Meanings of other options: · (.) Full stop: used to end a sentence (वाक्य समाप्त करने के लिए) · (,) Comma: used to separate parts within a sentence (वाक्य के भागों को अलग करने के लिए) · (:) Colon: used before a list or explanation (सूची या व्याख्या से पहले)