When two displacements represented by  are superimposed the motion is:
simple harmonic with amplitude 
simple harmonic with amplitude 
not a simple harmonic
simple harmonic with amplitude 
                
                  As we learnt in
Superposition of sinusoidal wave -
- wherein
Resultant equation is 
 
Since the frequencies for both S.H.M. are same resultant motion will be S.H.M.

Option 1)
simple harmonic with amplitude 
Incorrect
Option 2)
simple harmonic with amplitude 
Correct
Option 3)
not a simple harmonic
Incorrect
Option 4)
simple harmonic with amplitude 
Incorrect