CMAT Exam 2023 Shift 2 Solved Paper

The sentence I is grammatically correct. It uses the correct subordinating conjunction "whether" to introduce a subordinate clause indicating uncertainty about whether he will come or not. The structure "whether he will come or not" is commonly used to express doubt or uncertainty about a future event.
Sentence II is not grammatically correct. It uses the conjunction "that" instead of "whether," which is incorrect in this context. The correct construction, in this case, is to use "whether" to introduce the subordinate clause expressing uncertainty.
The correct option is A.