Identify the correct statement about the axes used in CNC machining: The Z axis is responsible for moving the tool towards the piece in turning ma...

Identify the correct statement about the axes used in CNC machining:

The Z axis is responsible for moving the tool towards the piece in turning machines and approaching the piece to the spindle in milling machines.
For CNC machining, nine axes are fully employed, divided into 3 groups: primary linear axes (X, Y, Z), primary rotation axes (A, B, and C), and auxiliary linear axes (U, V, and W).
The primary rotation axes are X, Y, and Z, the primary linear axes are A, B, and C, and the auxiliary rotation axes are U, V, and W.
The primary linear axes are X, Y, and Z, the secondary rotation axes are A, B, and C, and the primary linear axes are U, V, and W.
a) Only statement I is correct.
b) Statements II and III are correct.
c) Only statement II is correct.
d) Statements I and II are correct.