Select the most appropriate option to fill in the blank.
The team submitted the proposal on time, _______ they forgot to include the updated budget estimates.

Correct option is B

The correct option to fill in the blank is (B) but.

Explanation: The sentence contains two contrasting ideas: the timely submission of the proposal (positive) and the omission of budget estimates (negative). The coordinating conjunction 'but' is used to connect two statements when the second one contrasts with the first.

Example: He studied hard for the exam, but he failed to pass.

Information Booster: 'So' indicates result, 'Because' indicates reason, and 'And' indicates addition. Only 'but' provides the necessary contrast for this context.

So the correct answer is (b)