SHM

Q8 ans b
Sorry if the image is not clear.

@nishantthakre don't worry, the image is not blurry.
Now, come to your question. The trick behind it is to find the angular frequency of each function. If the angular frequencies are same , then they are in simple harmonic motion.
Look the hints.

@sarthakbasak
Sorry I am a beginner .
Can you tell me why the phase angles should be same for motion to be SHM?

@nishantthakre
Sorry, I made a mistake. It will be angular frequency. Not phase angle. I edited my earlier answerNow, this is the preliminary concept of shm. In shm all the particles have to move with a constant angular frequency. If angular frequency varies, then two particles will have different time period, different amplitude, different energy. Which is not possible. That's why we derive the equation, y=A sin (wt) where w= angular frequency= const.
Look in the 2nd option the function has different angular frequencies. Hence it will not undergo shm.