Your instrument, outside of music, is your own voice. If you love yourself and tell the world (using your 'instrument'), then you can feel fulfilled. This advice is good for anyone who feels like they aren't heard or seen, they can use their voice to speak up and create change for themselves and others.
Generally C, is the correct answer, however, C next time needs a transition word like; and, but, yet, however, or etc.
Answer: C
Hope this helps!
In concentration camps which they were in rooms that pumped gas