Magna flux is

A.A non-destructive inspection technique that makes use of magnetic field and magnetic particles to locate flaw in materials
B.An instrument using ultrasonic techniques for crack detection
C.An instrument used for inspection of weldings
D.An instrument used for precision measurements using magnetism and flux density
E.Intensity of X-rays required corresponding to thickness of a job for determination of defects.

Undercutting is

A.An operation of cutting extra wide threads
B.An operation of cutting a groove next to a shoulder on a piece of work
C.Cutting from the base of a work piece
D.An operation of cutting deep grooves
E.None of above