The lawyer was deceptively honest with his clients.
An oxymoron is a phrase of opposites in which the two opposing words are side by side. In this sentence, deceptively means not to be true and honest means to be true. These words are found together in the sentence with deceptively describing honest.
Antithesis can sometimes be confused with oxymoron. An antithesis when two phrases contradict each other. An example of this is Option A where the first half of the sentence contradicts the second half.
"The lawyer was deceptively <span>honest with his clients" is the only sentence that is an oxymoron, which requires a complete contradiction of terms such as this. </span>
