The correct option is B The changes in the geometry of the structure during the application of the loads is too small and the strains in the structure are directly proportional to the corresponding stresses.
The principle of superposition is stated as- 'the deflection at a given point in a structure produced by several loads acting simultaneously on the structure can be found by superposing deflections at the same point produced by loads acting individually.'
The principle of superposition can be applied only when-
1. stress-strain relationship is linear.
2. the geometry of the structure doesn't change with the application of load. i.e., strains are small
Hence answer is option (b).