Please answer A and B .

Dear student,
Please find below the answer:

A. 1. The correct option is (b). Wood is non-magnetic in nature.
2. The correct option is (c). The poles of a magnet can never be separated.
3. The correct option is (d). Repeated hammering of magnet leads to loss of magnetism. It is not a method of magnetisation.
4.  The correct option is (c). To demagnetise a magnet, it is either heated for some time or hammered repeatedly.
5. The correct option is (c). The south of a bar magnet will attract the north pole of a horseshoe magnet.
6. The correct option is (c). Electric doorbell contains an electromagnet.
7. The correct option is (b). Sailors use the directional property of magnets to find direction.

B. The correct option is (b). Magnets made of hard materials like steel, nickel and cobalt are called permanent magnets.

Hope this clears your doubt.
Regards.