Wrist drip is caused by the damage of the radial nerve bcz it is the one the innervates the extensor muscles . The cervical nerve roots of it are C5 to T1 bcz it originates from posterior cord of brachial plexus .. so A
Radial nerve.......root value:C5,6,7,8&T1......supplying extensor compartment of arm and forearm
Wrist drop is caused due to injury to the radial nerve having nerve root C-5 to T-1