Q. In the following question, out of four words given below, three are alike in some manner and fourth word is different. Find the different one.

Correct Answer: a) STETHOSCOPE

Explanation:
– Telescope, Microscope, and Periscope are optical instruments used for viewing (seeing) objects—far away, very small, or around obstacles.
– Stethoscope is used for listening to internal body sounds (like the heartbeat), not for viewing.
Hence, STETHOSCOPE is the odd one out.