Consider an electrode coating, performing the following functions:
1. Stabilize the arc
2. Control the rate at which the electrode melts
3. Control the flow of current
4. Enhance the quality of the joint
Which of these functions are correct?
(a) 1 and 2 only (b) 2 and 3 only
(c) 3 and 4 only (d) 1, 2 and 4