Most likely A but I could be wrong!
The doctor. most likely, is referring to the settling process. In this process, the muscles are still adjusting or on the process of healing so he is experiencing some back pains due to this. Once the muscles are settled in place, he would feel normal again.
The slowest drug absorption/response is definitely oral/digestion route.
The fastest drug response time route would be intravenous, the drugs directly enter the blood so it can work instantly. Snorting/inhaling drug still need time to be absorbed to the blood vessel. It might be fast enough if used for local response (example: asthma). The mechanism probably by mucosa diffusion so its similar to rectal or sublingual route.
His theory is primarily that our personality is formed by our positive and negative experiences in life, and that with each stage of his development, we experience certain stages in our personality development.
