Answer:
a. Bar A is a magnet
b. Bar B is a metal or magnetic material
c. Bar D is a non-magnetic material
Step-by-step explanation:
a. Bar A
Since B attracts both A and C, it shows that A and C are both magnetic. So, it is either B and A are magnets or B and C are magnets or A and C are magnets. Also, since A and C sometime attract one another and sometimes repel one another, it means that they attract when their poles are opposite and repel when their poles are negative. This show that both A and C are magnets. Thus, A is a magnet.
b. Bar B
Since B is attracted to both A and C and we know that both A and C are magnets, it implies that B is a magnetic material. Since it does not repel either A or C.
c. Bar D
Since D does not attract A, B or C, D is a non-magnetic material. Since, only a magnetic material can be attracted to magnets and we have established that both A and C are magnets and that B is magnetic. Since D is not also attracted to B, it implies that D is thus non-magnetic.