Assumption Que: Salesman in the guitar department

[Target2009]

When the salesman in the guitar department of a music store plays an electric guitar in the showroom, he sells more guitars than when he plays a classical guitar. The music store gives the salesman a 5% commission for every guitar that he sells. It can be concluded that the salesman enjoys playing on an electric guitar more than he does on a classical guitar.

The above conclusion is properly drawn if which of the following is assumed?

A: The number of guitars sold could be increased if there were seperate showrooms for electric and classical guitars.
B: The salesman's enjoyment as a guitarist is based only on the amount of money he earns by playing.
C: The salesman's commission is higher than that offered by most music stores.
D: An electric guitar is a far more versatile instrument than a classical guitar.
E: The skills needed to play an electric guitar are slightly different to those needed to play a classical one.

Source : Master Gmat.
Request: Kindly support your choice with explanation.

[sumit88]

When the salesman in the guitar department of a music store plays an electric guitar in the showroom, he sells more guitars than when he plays a classical guitar. The music store gives the salesman a 5% commission for every guitar that he sells. It can be concluded that the salesman enjoys playing on an electric guitar more than he does on a classical guitar.

The above conclusion is properly drawn if which of the following is assumed?

A: The number of guitars sold could be increased if there were seperate showrooms for electric and classical guitars.
B: The salesman's enjoyment as a guitarist is based only on the amount of money he earns by playing.
C: The salesman's commission is higher than that offered by most music stores.
D: An electric guitar is a far more versatile instrument than a classical guitar.
E: The skills needed to play an electric guitar are slightly different to those needed to play a classical one.

Source : Master Gmat.
Request: Kindly support your choice with explanation.

IMO B.

when salesman plays electric guitar --> more sales-->salesman gets more commission -->

Conclusion: salesman enjoys playing classical guitar. This can be true if
[missing assumption]: salesman enjoyment = amount he earns playing, is true.

[HSPA]

It is a battle btw B and D.

I have chosen D. I did liked B except for the word ONLY.
B is a little extreme

[sumit88]

But I think in missing assumption type questions "only" if the particular assumption is correct conclusion holds water..

Please correct me if I am missing something..

[ColumbiaVC]

B

[xxpatzz]

IMO:B

I think D doesn't really provide the assumption that will link salesman's enjoyment and the sales.

[Target2009]

OA: B

[jaguar123]

D is irrelevant. B is only answer sensible answer choice left after elemination.
But im not sure if the negation test works for this choice.

[singalong]

B completely destroys the argument because the argument mentions about the salesman being paid more for electric guitar.D doesn't mention anything about this.D could come as a close second after B I think.