The correct option is B Offensive
The given word 'defensive' means to protect yourself or someone else.
'Offensive' means to act aggressively or say something that would upset or annoy someone, it is the opposite in meaning to 'defensive'. In other words, 'offensive' is an antonym of 'defensive'. Consider the sentences: 'She said something offensive to him' and 'She was in a defensive mood when someone mocked her.'.
Hence, option B is correct.
'Safe' means 'protected from some form of danger or harm', it is similar in meaning to defensive, hence it can't be its antonym.
'Escape' means to break free from some sort of confinement, it isn't the opposite of defensive.
'Protective' is synonymous to 'defensive', it refers to the quality of protecting someone, making them feel safe and secure.
These words aren't antonyms, in fact, A and D are synonyms; hence options A, C and D are incorrect.