In statement given below, a part of the sentence is enclosed in quotation marks. Below are given alternatives to the quotes part which may improve the sentence. Choose the correct alternative. In case no improvement is needed, option 'D' is the answer.No one could explain how a calm and balanced person like him could "penetrate" such a mindless act on his friends.

• A. perpetuate
• B. perpetrate
• C. precipitate
• D. No improvement