Identify the adverbial clause in the following sentence:

“I knew that I had come face to face with someone whose mere personalist was so fascinating that, if I allowed it to do so, it would absorb my whole nature, my whole soul, my very art itself.”

A. I knew that I had come face to face with someone whose mere personalist was so fascinating that

B. if I allowed it to do so, it would absorb my whole nature

C. my very art itself

D. my whole soul