Three metals P, Q and R show different expansion
properties when heated. The metal P expands less than Q and metal Q expands less than R. Aditi has made a circuit for a fire alarm in which she wants to use a bimetallic strip to cause completion of the circuit (shown in figure) so that the alarm bell can ring.
Which of the following bimetallic strips should she use at place X?
A
B
C
D
Can someone explain