Ans 3:
Class : Class 8
There is a lot of confusion but the correct answer id C 'BAND' because a choir is a term used for singers not musicians (musicians are not specifically singers). So it is ' A BAND OF MUSICIANS' and 'A CHOIR OF SINGERS'. P.S Hope that helped!
Ans 4:
Class : Class 3
The answer should be band 'cos a choir has only singers but a band has all type of musicians like drummers , trumpeters etc.