The correct answer is to B. De-emphasize the subject.
Very often the subject can be completely omitted.
Burglars committed the crime
The crime was committed (by the burglars).
In the passive version, the subject is irrelevant.
The correct answer is the first one.
He describes Mrs. Miller's behavior as "unprecedented." By this, he is saying that, of all the parents he has ever known, her behavior is unusual, singular, or unique.
Quite simply, it is strange that she would allow her daughter to run around town with a strange man. Mrs. Miller's behavior is more than silly -- it is downright unheard of.
The answer is c, secretive :)
What grade are you doing this for lol