Assertion $(A)$:The stretching of a spring is determined by the shear modulus of the material of the spring.
Reason $(R)$:A coil spring of copper has more tensile strength than a steel spring of same dimensions.
In the light of the above statements, choose the most appropriate answer from the options given below:

| List-$I$ | List-$II$ |
| $(A)$ A force thatrestores anelastic body of unit area to its original state | $(I)$ Bulkmodulus |
| $(B)$ Two equal andopposite forcesparallel toopposite faces | $(II)$Young'smodulus |
| $(C)$Forcesperpendiculareverywhere tothe surface perunit areasameeverywhere | $(III)$ Stress |
| $(D)$Two equal andopposite forceperpendicular toopposite faces | $(IV)$ Shearmodulus |
Choose the correct answer from the options given below: