Select the most appropriate antonym to substitute the bracketed word in the given sentence.

So it would appear that from now on I am going to have to be more (tactful) and diplomatic in my meanderings.

Ungracious 

The correct answer is option 4. Ungracious.

"Tactful" refers to being careful not to offend or upset others, often by saying or doing the right thing in a sensitive situation.

The antonym we're looking for should describe the opposite behavior, which would involve being insensitive or not considering others' feelings.

"Ungracious" fits this description perfectly. It means lacking in courtesy or politeness, implying a lack of consideration for others' feelings.

Therefore, "ungracious" is the appropriate antonym for "tactful" because it represents the opposite characteristic—being insensitive or lacking in politeness instead of being careful and considerate.