Find the odd musical instrument (wind vs strings): Select the instrument that does not belong to the string family.

Introduction / Context:
Instrument grouping by sound-production mechanism is a standard, reliable method in reasoning tests. When three instruments are strings and one is a wind instrument, the wind instrument is the natural outlier independent of cultural origin or playing posture.

Given Data / Assumptions:

• Sitar: plucked string instrument.
• Violin: bowed string instrument.
• Santoor: struck/plucked string instrument (a type of hammered dulcimer in Indian music).
• Flute: wind instrument; tone produced by air stream across an embouchure hole or fipple.

Concept / Approach:
Classify into families: chordophones (strings) versus aerophones (winds). Three items are chordophones; one is an aerophone.

Step-by-Step Solution:

Verification / Alternative check:
Compare required technique: plucking/bowing/striking a string versus blowing air. This confirms the family separation.

Why Other Options Are Wrong:
They share the core string property despite differences in technique (bowed, plucked, hammered).

Common Pitfalls:
Do not conflate unusual playing technique (hammered strings in santoor) with a different family; the sound source remains vibrating strings.

Final Answer:
Flute