I keep my . . . . . . . . opinions to myself.

special
private
particular
especial

The correct answer is B. private.

A private opinion is one that is not shared with others. It is something that you keep to yourself, often because you do not want to offend or upset someone. Private opinions can be about anything, from personal preferences to political beliefs.

The other options are not as accurate. A special opinion is one that is considered to be important or unique. A particular opinion is one that is specific to a particular person or group. An especial opinion is a formal or official opinion.

In the context of the question, it is clear that the speaker is keeping their opinion to themselves because they do not want to share it with others. This suggests that the opinion is private.