The stimulus doesn't say they are ONLY motivated by financial gain; it just says financial gain is a motivator for them. They could also be motivated by other things, including love of discovery. Accordingly, we just can't say one way or the other whether they are motivated at all by love of discovery.
#21 - Essayist: Winners of a Nobel prize for science, who
I will chime in in order to help future students.
The stimulus states that UNLIKE professionals, amateurs are SOLEY motived by the "love of discovery ALONE"
We can infer that amateurs have only one motivating factor. Professionals in contrast can have multiple. (they are unlike amateurs).
That is true and is why answer choice (C) is correct. The motivations of amateurs are always singular; the motivations of professionals can be mixed. So both your statement and Emily's statement are correct about their respective motivations.