What is the proper technique for performing chest compressions during cpr? a) use upper body weight to compress the chest about one inch, at a rate of 60 compressions per minute b) use all the force of your arm strength to compress the chest about two inches, at a rate of 60 compressions per minute c) use upper body weight to compress the chest about two inches, at a rate of 100 compressions per minute d) use all the force of your arm strength to compress the chest about one inch, at a rate of 100 compressions per minute