After each of the following sentences, a list of possible interpretations of the sentence is given. Choose the interpretation that you consider most appropriate for each sentence.
Although Aliyu was acquitted by the court for want of evidence, the police still kept a tab on him. This means that they

• A.kept him under close observation
• B.set a trap to catch him again
• C.attached a tag to his clothes
• D.kept him behind bars.