The correct option is A Acquitted
The option with the opposite meaning is the correct one.
The
underlined word 'sentenced' means 'to declare a punishment decided for a criminal or an offender'. The culprit here is the offender who is punished.
'Acquitted' means that a person is freed from a criminal charge by the verdict that he is not guilty. It's the opposite of the underlined word.
'Pardoned' is also similar in meaning to acquitted. The difference being: the former means that you're not given a punishment even though you are guilty. You are forgiven for your offense.
In contrast, the latter means that you have been declared innocent. Hence, the latter is most opposite in meaning.
So, option A is correct and D is incorrect.
'Punished' is similar to the underlined word, hence it isn't opposite in meaning and B is incorrect.
'Relieved' refers to being freed from a particular duty or responsibility; it does not relate to a 'sentence' or a punishment. Hence it isn't its opposite and C is incorrect.