Is your doctor dead set on a C-Section? I would try to avoid it if I were you. Everything is so much more difficult with a c-section, including the recovery and healing, taking care of the baby and even breastfeeding.
Ultrasounds are very notorious for being off on their measurements. I was induced early with one of my babies. The doctors said she stopped growing. I was getting weekly ultrasounds and the last 3 said she was only 4 lbs. They induced me and my baby was 6 lbs 4 ozs.
I wouldn't put a lot of faith into that 10lb measurement unless you have gestational diabetes.